To see the other types of publications on this topic, follow the link: Raman coherence.
Dissertations / Theses on the topic 'Raman coherence'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Raman coherence.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Egodage, Kokila Dampali [Verfasser], Jürgen [Gutachter] Popp, and Volker [Gutachter] Deckert. "Combination of optical coherence tomography and Raman spectroscopy / Kokila Dampali Egodage ; Gutachter: Jürgen Popp, Volker Deckert." Jena : Friedrich-Schiller-Universität Jena, 2018. http://d-nb.info/1170587712/34.
Full text
2
Stone, N. "Raman spectroscopy of biological tissue for application in optical diagnosis of malignancy." Thesis, Department of Environmental and Ordnance Systems, 2009. http://hdl.handle.net/1826/4015.
Full textAbstract:
The utilisation of near-infraredR aman spectroscopyfo r the discrimination of cancersa nd
pre-cancers from normal tissue in the acro-digestive tract has been evaluated. A
commercially available Raman microspectrometehr as been modified to provide optimum
throughput, sensitivity and fluorescence suppression for epithelial tissue measurements.
Laser excitation at 830nmw as demonstratedto be optimum. High quality (SN ratio 15-20)
NIR-Raman spectrah ave been acquired from oesophageaal nd laryngeal tissues in time
scales under 30 seconds.
Pathological groupings covering the full range of normal and neoplastic tissues in the organs
of interest have been studied. Both fresh (snap frozen) and formalin fixed tissue samples
were investigated,f irstly to indicate whether tissue-typesc an be distinguishedi n vivo and
secondlyt o demonstrateth e use of Raman spectroscopya s a tool for classificationi n the
pathology lab.
Results using multivariate statistical techniques to distinguish between spectra from
specimens exhibiting different tissue pathologies have been extremely promising. Crossvalidation
of the spectral predictive models has shown that three groups of larynx tissue
can be separated with sensitivities and specificities of between 86 and 90% and 87 and
95% respectively. Oesophageal prediction models have demonstrated sensitivities and
specificities of 84 to 97% and 93 to 98% respectively for a three-group consensus model
and 73 to 100% and 92 to 100% for an eight-groupc onsensusm odel.
Epithelial tissues including stomach, tonsil, endometrium, bladder and prostate have been
studiedt o identify further tissuesw hereR amans pectroscopym ay be employedf or detection
of disease.S pectraw ere similar to those obtainedf rom oesophagusa nd larynx, although
sufficiently different for distinct discriminant models to be required. This work has
demonstratedth e genericn atureo f Ramans pectroscopyfo r the detectiona nd classification
of cancersa nd pre-cancerousle sionsi n many tissues.T he evidencep rovided by this study
indicatest hat utilisation of Ramans pectroscopyfo r non-invasived etectiona nd classification
of diseaseis a distinct possibility. Potentiald ifficulties in the transferabilityf rom in vitro to
in vivo have been evaluated and no significant barriers have been observed. However,
further in vivo probe development and optimisation will be required before 'optical biopsy'
with Ramans pectroscopyc anb ecomea reality.
3
Stone, Nicholas. "Raman spectroscopy of biological tissue for application in optical diagnosis of malignancy." Thesis, Cranfield University, 2001. http://dspace.lib.cranfield.ac.uk/handle/1826/4015.
Full textAbstract:
The utilisation of near-infrared Raman spectroscopy for the discrimination of cancers and pre-cancers from normal tissue in the acro-digestive tract has been evaluated. A commercially available Raman microspectrometer has been modified to provide optimum throughput, sensitivity and fluorescence suppression for epithelial tissue measurements. Laser excitation at 830nm was demonstrated to be optimum. High quality (SN ratio 15-20) NIR-Raman spectra have been acquired from oesophageal and laryngeal tissues in time scales under 30 seconds. Pathological groupings covering the full range of normal and neoplastic tissues in the organs of interest have been studied. Both fresh (snap frozen) and formalin fixed tissue samples were investigated, firstly to indicate whether tissue-types can be distinguished in vivo and secondly to demonstrate the use of Raman spectroscopy as a tool for classification in the pathology lab. Results using multivariate statistical techniques to distinguish between spectra from specimens exhibiting different tissue pathologies have been extremely promising. Cross-validation of the spectral predictive models has shown that three groups of larynx tissue can be separated with sensitivities and specificities of between 86 and 90% and 87 and 95% respectively. Oesophageal prediction models have demonstrated sensitivities and specificities of 84 to 97% and 93 to 98% respectively for a three-group consensus model and 73 to 100% and 92 to 100% for an eight-group consensus model. Epithelial tissues including stomach, tonsil, endometrium, bladder and prostate have been studied to identify further tissues where Raman spectroscopy may be employed for detection of disease. Spectra were similar to those obtained from oesophagus and larynx, although sufficiently different for distinct discriminant models to be required. This work has demonstrated the generic nature of Raman spectroscopy for the detection and classification of cancers and pre-cancerous lesions in many tissues. The evidence provided by this study indicates that utilisation of Raman spectroscopy for non-invasive detection and classification of disease is a distinct possibility. Potential difficulties in the transferability from in vitro to in vivo have been evaluated and no significant barriers have been observed. However, further in vivo probe development and optimisation will be required before 'optical biopsy' with Raman spectroscopy can become a reality.
4
Balagopal, Bavishna. "Advanced methods for enhanced sensing in biomedical Raman spectroscopy." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6343.
Full textAbstract:
Raman spectroscopy is a powerful tool in the field of biomedicine for disease diagnosis owing to its potential to provide the molecular fingerprint of biological samples. However due to the inherent weak nature of the Raman process, there is a constant quest for enhancing the sensitivity of this technique for enhanced diagnostic efficiency. This thesis focuses on achieving this goal by integrating advanced methods with Raman spectroscopy. Firstly this thesis explores the applicability of a laser based fluorescence suppression technique – Wavelength Modulated Raman Spectroscopy (WMRS) - for suppressing the broad luminescence background which often obscure the Raman peaks. The WMRS technique was optimized for its applications in single cell studies and tissue studies for enhanced sensing without compromising the throughput. It has been demonstrated that the optimized parameter would help to chemically profile single cell within 6 s. A two fold enhancement in SNR of Raman bands was demonstrated when WMRS was implemented in fiber Raman based systems for tissue analysis. The suitability of WMRS on highly sensitive single molecule detection techniques such as Surface Enhanced Raman Spectroscopy (SERS) and Surface Enhanced Resonance Raman Spectroscopy (SERRS) was also explored. Further this optimized technique was successfully used to address an important biological problem in the field of immunology. This involved label-free identification of major immune cell subsets from human blood. Later part of this thesis explores a multimodal approach where Raman spectroscopy was combined with Optical Coherence Tomography (OCT) for enhanced diagnostic sensitivity (>10%). This approach was used to successfully discriminate between ex-vivo adenocarcinoma tissues and normal colon tissues. Finally this thesis explores the design and implementation of a specialized fiber Raman probe that is compatible with surgical environments. This probe was originally developed to be compatible with Magnetic Resonance Imaging (MRI) environment. It has the potential to be used for performing minimally invasive optical biopsy during interventional MRI procedures.
5
Ignacchiti, Jim. "Contrôle et caractérisation de la cohérence Raman induite par bruit quantique dans des fibres creuses remplies de gaz". Electronic Thesis or Diss., Limoges, 2024. http://www.theses.fr/2024LIMO0056.
Full textAbstract:
Ces travaux de thèse portent sur la conception, la mise en œuvre et l’utilisation d’une plateforme expérimentale et de simulations numériques visant à exciter et amplifier la cohérence Raman de façon contrôlée à partir du bruit quantique. L’objectif est d’explorer la diffusion Raman stimulée dans des fibres creuses comme un moyen de générer des peignes de fréquences optiques cohérents, avec une largeur spectrale multiple-octaves, et ainsi créer un outil pour produire des fonctions d’ondes optiques arbitraires, telles que des impulsions attosecondes ou des lasers à modes verrouillés. Le principe repose sur l’excitation d’un gaz contenu dans une fibre à cristal photonique à cœur creux (HCPCF) par des impulsions laser ultrabrèves de telle sorte qu’un seul des modes spatio-temporels cohérents et indépendants de l’émission spontanée de la radiation Stokes soit excité et amplifié. Cette approche novatrice assure une modulation de phase du champ du laser d’excitation à des fréquences très élevées et sans bruit de phase. Elle se distingue des techniques existantes, telles que la modulation moléculaire, par l’absence de besoin d’un deuxième laser. Cependant, cette méthode nécessite un guide optique unimodal et un gain Raman exceptionnellement élevé. Dans ce contexte, ces travaux se sont ainsi focalisés sur la génération et la mesure de la cohérence intra et inter-impulsionnelle du peigne Raman afin d’évaluer son potentiel pour les applications mentionnées précédemment. Pour ce faire, un modèle théorique de la diffusion Raman stimulée en régime impulsionnel a été développé, soulignant l’intérêt du régime transitoire, qui amplifie le champ Stokes en un seul mode temporel. Des simulations numériques ont ensuite détaillé la dynamique du champ Stokes à travers le milieu Raman, en prenant en compte des facteurs tels que la déplétion du laser. Par ailleurs, une fibre optique à cœur creux hybride a été spécifiquement développée, offrant de faibles pertes linéiques (quelques dB/km à 1030 nm) et un guidage unimodal exceptionnel (MPI jusqu’à −47 dB), assurant ainsi la cohérence spatiale du peigne Raman. Deux bancs expérimentaux ont ensuite été réalisés pour examiner la cohérence du peigne, en commençant par l’aspect intra-impulsionnel. Un laser infrarouge réglable en durée d’impulsion, en énergie et en taux de répétition a été couplé dans la fibre remplie de dihydrogène pour générer le peigne, puis analysé à la sortie avec un interféromètre Mach-Zehnder à haute résolution temporelle (∼ fs) et large plage dynamique (environ 50 ps). Les résultats ont montré qu’en travaillant dans la gamme 3 − 10 ps et 1 − 10 µJ, les effets parasites, comme l’effet Kerr, sont minimisés, et la cohérence mutuelle est proche de l’unité pour toutes les raies de Stokes et anti-Stokes du 1er ordre, comme confirmé par les calculs numériques. L’étude de la cohérence inter-impulsionnelle a révélé un comportement complexe pour des impulsions espacées de moins de 1 ns et une diminution de la cohérence suivant la valeur du temps de relaxation de la cohérence (∼ 2 ns) pour des délais plus longs entre les impulsions. Ces résultats soulignent l’importance de contrôler l’énergie et le délai des impulsions pour maintenir une haute cohérence, et suggèrent que des lasers d’excitation à des cadences de l’ordre de 400 MHz ou plus peuvent générer des lasers à modes verrouillés basés sur notre approche. En conclusion, les avancées réalisées durant cette thèse sur les propriétés de cohérence des peignes de fréquence montrent le potentiel de la diffusion Raman stimulée dans les HCPCFs pour la synthèse d’ondes optiques, et ouvrent la voie à d’autres applications comme la conversion de fréquence pour l’optique quantique, le piégeage optique et le refroidissement moléculaire<br>This thesis addresses the design, implementation, and use of an experimental and numerical simulation platform aimed at exciting and amplifying Raman coherence in a controlled manner from quantum noise. The long term objective is to explore stimulated Raman scattering in hollow-core fiber as a means to generate coherent optical frequency combs with a multi-octave spectral width, thus creating a tool for generating arbitrary optical wave functions, such as attosecond pulses, or mode-locked lasers. The principle is based on the excitation of a gas contained in a hollow-core photonic crystal fiber (HCPCF) by ultrashort laser pulses, in such a way that only one of the coherent and independent spatiotemporal modes of the spontaneous Stokes radiation is excited and amplified. This innovative approach ensures phase modulation of the excitation laser field at very high frequencies without phase noise. It differs from existing techniques, such as molecular modulation, by eliminating the need for a second laser. However, this method requires a single-mode optical guide and exceptionally high Raman gain. In this context, this work focuses then on the generation and measurement of the intra and inter-pulse coherence of the Raman comb to evaluate its potential for the aforementioned applications. To this end, a theoretical model of stimulated Raman scattering in the impulsive regime was developed, highlighting the interest of the transient regime, which amplifies the Stokes field in a single temporal mode. Numerical simulations then detailed the dynamics of the Stokes field through the Raman medium, taking into account factors such as laser depletion. Furthermore, a specific hybrid hollow-core optical fiber was developed, offering low linear losses (a few dB/km at 1030 nm) and exceptional single-mode guidance (MPI up to −47 dB), thus ensuring the spatial coherence of the Raman comb. Two experimental setups were then realized to examine the comb’s coherence, starting with the intra-pulse aspect. An infrared laser adjustable in pulse duration, energy, and repetition rate was coupled into the hydrogen-filled fiber to generate the comb, then analyzed at the output with a Mach-Zehnder interferometer with high temporal resolution (∼ fs) and wide dynamic range (approximately 50 ps). The results showed that working in the range of 3 − 10 ps and 1 − 10 µJ minimizes parasitic effects such as the Kerr effect, and the mutual coherence is close to unity for all first-order Stokes and anti-Stokes lines, as confirmed by numerical calculations. The study of inter-pulse coherence revealed a complex behavior for pulses spaced less than 1 ns apart and a decrease in coherence corresponding to the coherence relaxation time (∼ 2 ns) for longer delays between pulses. These results highlight the importance of controlling the energy and delay of pulses to maintain high coherence and suggest that excitation lasers with repetition rates around 400 MHz or more can generate mode-locked lasers based on our approach. In conclusion, the advances made during this thesis on the coherence properties of frequency combs demonstrate the potential of stimulated Raman scattering in HCPCFs for optical wave synthesis and pave the way for other applications such as frequency conversion for quantum optics, optical trapping, and molecular cooling
6
Perrot, Jean-Luc. "Explorations optiques multimodales et multiéchelles non invasives appliquées au revêtement cutanéomuqueux , étendues à l'appareil oculaire antérieur." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSES010/document.
Full textAbstract:
Après une introduction brève de l’historique de l’imagerie dermatologique non invasive, ce travail est divisé 3 parties. 1) Présentation d’un projet de développement d’un tomographe à cohérence optique miniaturisé, peu onéreu devant permettre une diffusion de cette technique aux dermatologues exerçant en dehors des hôpitaux. Il s’agi d’un projet ANR DOCT-VCSEL Portable Optical Coherence Tomography with MEMS-VCSEL swept- sources for skin analysis ANR 2015 / Défi sociétal « Vie, Santé et Bien-Etre » Axe 13 « Technologies pour la santé » 2) Présentation d’un projet dont le but est l’identification de lésions cutanées cancéreuses au moyen d’un nouvel OCT haute définition développé par la société DAMAE, issue de l’Institut supérieur d’Optique de Palaiseau. Il s’agit d’un dispositif qui sera dans un premier temps réservé aux centre d’excellence en imagerie dermatologique. 3) la reprise des 52 publications ayant trait à l’imagerie cutanée auxquelles j’ai participé et référencées dans les bases de données internationales au 31 décembre 2016. Ce travail couvre l’ensemble de l’imagerie non invasive dermatologique moderne et aborde des sujets qui n’avaient jamais été étudié de la sorte. Notamment les muqueuses et l’appareil oculaire antérieur mais aussi l’identification par microscopie confocale des marge chirurgicales ou l’association microscopie confocale spectrométrie Raman<br>After a brief introduction to the history of non-invasive dermatological imaging, this work is divided into 3 parts. 1) Presentation of a project for the development of a low-cost miniaturized optical coherence tomograph to allow dissemination of this technique to dermatologists practicing outside hospitals. This is an ANR project: DOCT-VCSEL Portable Optical Coherence Tomography with MEMS-VCSEL swept-sources for skin analysis ANR 2015 / Societal Challenge "Life, Health and Welfare" Axis 13 “Technologies for Health" 2) Presentation of a project whose goal is the identification of cancer skin lesions by means of a new high definition OCT developed by the company DAMAE, resulting from the Higher Institute of Optics of Palaiseau. It is a device that will initially be reserved for centers of excellence in dermatological imaging. 3) Presentation of 52 publications related to skin imaging, in which I participated, and referenced in the international databases as of December 31, 2016. This work covers all modern dermatological non-invasive imaging and addresses Subjects that had never been studied in this way. Notably the mucous membranes and the anterior ocular apparatus but also the identification by confocal microscopy of the surgical margins or the association confocal microscopy Raman spectrometry
7
Smith, Brett. "Coherent Anti-Stokes Raman Scattering Miniaturized Microscope." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24281.
Full textAbstract:
Microscopy techniques have been developed and refined over multiple decades, but innovation around single photon modalities has slowed. The advancement of the utility of information acquired, and minimum resolution available is seemingly reaching an asymptote. The fusion of light microscopy and well-studied nonlinear processes has broken through this barrier and enabled the collection of vast amounts of additional information beyond the topographical information relayed by traditional microscopes. Through nonlinear imaging modalities, chemical information can also be extracted from tissue. Nonlinear microscopy also can beat the resolution limit caused by diffraction, and offers up three-dimensional capabilities. The power of nonlinear imaging has been demonstrated by countless research groups, solidifying it as a major player in biomedical imaging.
The value of a nonlinear imaging system could be enhanced if a reduction in size would permit the insertion into bodily cavities, as has been demonstrated by linear imaging endoscopes. The miniaturization of single photon imaging devices has led to significant advancements in diagnostics and treatment in the medical field. Much more information can be extracted from a patient if the tissue can be imaged in vivo, a capability that traditional, bulky, table top microscopes cannot offer. The development of new technologies in optics has enabled the miniaturization of many critical components of standard microscopes. It is possible to combine nonlinear techniques with these miniaturized elements into a portable, hand held microscope that can be applied to various facets of the biomedical field.
The research demonstrated in this thesis is based on the selection, testing and assembly of several miniaturized optical components for use as a nonlinear imaging device. This thesis is the first demonstration of a fibre delivered, microelectromechanical systems mirror with miniaturized optics housed in a portable, hand held package. Specifically, it is designed for coherent anti-Stokes Raman scattering, second harmonic generation, and two-photon excitation fluorescence imaging. Depending on the modality being exploited, different chemical information can be extracted from the sample being imaged. This miniaturized microscope can be applied to diagnostics and treatments of spinal cord diseases and injuries, atherosclerosis research, cancer tumour identification and a plethora of other biomedical applications. The device that will be revealed in the upcoming text is validated by demonstrating all designed-for nonlinear modalities, and later will be used to perform serialized imaging of myelin of a single specimen over time.
8
Kavanagh, Thomas Christopher. "Hyperspectral Coherent Anti-Stokes Raman Scattering Microscopy." Thesis, King's College London (University of London), 2017. https://kclpure.kcl.ac.uk/portal/en/theses/hyperspectral-coherent-antistokes-raman-scattering-microscopy(14952c6f-e333-4596-950f-29be55cbca44).html.
Full textAbstract:
Possessing high three dimensional optical sectioning capabilities and deriving chemical contrast from the intrinsic molecular vibrations of the sample, coherent anti-Stokes Raman scattering (CARS) microscopy has the ability to deliver high sensitivity non-invasive biological imaging. It is, however, accompanied by a deleterious non-resonant background (NRB) which acts to reduce the contrast and severely complicate analysis. Computational approaches are currently favoured for removing this NRB; however, these result in significant spectrally varying errors. This thesis concerns the development and subsequent implementation of a CARS platform employing a novel, all-optical, non-resonant background removal mechanism: Spectral Interferometric Polarisation Coherent Anti-Stokes Raman Scattering (SIPCARS). Exploiting the phase change that accompanies a Raman resonance and employing an elliptical pump/probe beam and linear Stokes beam, SIPCARS allows the complete removal of the NRB. The resulting SIPCARS spectra encode mode symmetry information into the amplitude response which can be directly related to polarisation resolved spontaneous Raman scattering spectra. Verification of the SIPCARS methodology was achieved using spectra acquired from pure liquid samples which were in complete agreement with the corresponding polarisation resolved spontaneous Raman scattering spectra. The multiplexing limit of the system was assessed using several multi-component polymer bead mixtures and a lower limit of four determined. High signal-to-noise ratio SIPCARS imaging of a HeLa cell in the vibrational fingerprint region was acquired, from which it was possible to identify lipid droplets and subsequently, by producing ratio images, assess their degree of lipid unsaturation and the level of oxidised lipid content. The effect of a naturally derived phytotherapeutic lipid metabolism altering drug on the lipid droplets, contained within wild type N2 Caenorhabditis elegans nematodes, was addressed using SIPCARS. Assessing lipid unsaturation and area fraction, the drug was shown to produce a marked effect: a significant reduction in storage of saturated fatty acids post exposure. Additionally the ability of SIPCARS to differentiate between a variety of different C. elegans mutants was also demonstrated. SIPCARS currently provides perhaps the only viable route to attain truly quantitative NRB-free CARS data; however, expanding on the foundation provided by this thesis, and following further development, it has the potential for profound implications in a wide range of areas including fundamental life sciences research, novel drug characterisation and histopathology.
9
Viranna, Narendra Balaguru. "Coherent anti-Stokes Raman spectroscopy of diamond." Master's thesis, University of Cape Town, 1997. http://hdl.handle.net/11427/26229.
Full textAbstract:
Experiments were performed to investigate Coherent Anti-Stokes Raman Scattering (CARS) in diamond. Aspects of this type of non-linear scattering are presented theoretically, and various experimental configurations were attempted in order to study them. These included the dependence of the CARS signal intensity on the intensities of the two exciting frequency-doubled Nd:YAG (pump) and dye (Stokes) lasers, the variation of the CARS signal polarization as a function of the lasers' polarization, and the dependence of the CARS signal intensity on the phase mismatch of the laser beams. The phase mismatch measurement confirmed the predicted sinc² nature of the CARS signal intensity, while· the polarization measurements provided new information on the ratio of the non-vanishing components of the cubic susceptibility x³ of diamond. The CARS signal intensity was found to change linearly with the dye laser intensity and quadratically with the Nd: Y AG laser intensity. The CARS signal was found at the predicted 1332 cm⁻¹ shift from the doubled Nd:YAG emission, and its linewidth of 1.2 cm⁻¹ is in agreement with the spontaneous Raman linewidth.The spectral data were fitted to a modified Voigt profile containing the non-resonant cubic susceptibility contribution, and this allowed us to establish the ratio of the resonant and non-resonant parts of x³. An attempt to generate Stimulated Raman Scattering in diamond was unsuccessful.
10
Beaman, R. A. "Two beam coherent spectroscopy." Thesis, Cardiff University, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379609.
Full text
11
Tan, Mingming. "Raman fibre laser based amplification in coherent transmission systems." Thesis, Aston University, 2016. http://publications.aston.ac.uk/28899/.
Full textAbstract:
The thesis presents a detailed study of different Raman fibre laser (RFL) based amplification techniques and their applications in long-haul/unrepeatered coherent transmission systems. RFL based amplifications techniques were characterised from different aspects, including signal/noise power distributions, relative intensity noise (RIN), mode structures of induced Raman fibre lasers, and so on. It was found for the first time that RFL based amplification techniques could be divided into three categories in terms of the fibre laser regime, which were Fabry-Perot fibre laser with two FBGs, weak Fabry-Perot fibre laser with one FBG and very low reflection near the input, and random distributed feedback (DFB) fibre laser with one FBG. It was also found that lowering the reflection near the input could mitigate the RIN of the signal significantly, thanks to the reduced efficiency of the Stokes shift from the FW-propagated pump. In order to evaluate the transmission performance, different RFL based amplifiers were evaluated and optimised in long-haul coherent transmission systems. The results showed that Fabry-Perot fibre laser based amplifier with two FBGs gave >4.15 dB Q factor penalty using symmetrical bidirectional pumping, as the RIN of the signal was increased significantly. However, random distributed feedback fibre laser based amplifier with one FBG could mitigate the RIN of the signal, which enabled the use of bidirectional second order pumping and consequently give the best transmission performance up to 7915 km. Furthermore, using random DFB fibre laser based amplifier was proved to be effective to combat the nonlinear impairment, and the maximum reach was enhanced by >28% in mid-link single/dual band optical phase conjugator (OPC) transmission systems. In addition, unrepeatered transmission over >350 km fibre length using RFL based amplification technique were presented experimentally using DP-QPSK and DP-16QAM transmitter.
12
Yousif, Huda. "Coherent Anti-Stokes Raman Scattering Microscopy for Biomedical Applications." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37315.
Full textAbstract:
Coherent anti-Stokes Raman scattering (CARS) microscopy is considered as a powerful tool for non-invasive chemical imaging of biological samples. CARS microscopy provides an endogenous contrast mechanism that it is sensitive to molecular vibrations. CARS microscopy is recognized as a great imaging system, especially in vivo experiments since it eliminates the need for the contrast agents.
In this thesis, CARS microscopy/spectroscopy is built from scratch by employing a single (Ti-Sapphire) laser source generating 65 femtosecond laser pulses centered at 800 nm wavelength. Two closely lying zero dispersion photonic crystal fiber (PCF) is used to generate the supercontinuum for the Stokes beam to generate CARS at 2885 cm-1 to match lipids rich vibrational frequency. XY galvanometers are used for laser raster scanning across the sample. The initial generation of CARS signal was in the forward direction. After guaranteeing a strong CARS signal, images for chemical and biological samples were taken. To achieve a multimodal imaging technique, CARS microscopy imaging system is combined with two- photon excitation fluorescent (TPEF) and second harmonic generation (SHG) imaging techniques, where various information was extracted from the imaged samples. Images with our CARS microscopy show a good resolution and sensitivity.
The second part of my work is to reduce the footprint for this setup to make it more suitable for use in clinical applications. For that reason, I integrated a homebuilt endoscope and all fiber femtosecond laser source together to get a fiber based imaging system. Proof of principal for the integrated system is achieved by obtaining a reasonable agreement in accuracy and resolution to those obtained by the endoscope driven by Ti-sapphire laser.
13
Keogh, Gary Peter. "The application of coherent Raman scattering to molecular photonics." Thesis, Imperial College London, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243375.
Full text
14
Webster, Simon. "Raman sideband cooling and coherent manipulation of trapped ions." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424740.
Full text
15
Bégin, Steve. "Beyond imaging with coherent anti-Stokes Raman scattering microscopy." Doctoral thesis, Université Laval, 2014. http://hdl.handle.net/20.500.11794/25795.
Full textAbstract:
La microscopie optique permet de visualiser des échantillons biologiques avec une bonne sensibilité et une résolution spatiale élevée tout en interférant peu avec les échantillons. La microscopie par diffusion Raman cohérente (CARS) est une technique de microscopie non linéaire basée sur l’effet Raman qui a comme avantage de fournir un mécanisme de contraste endogène sensible aux vibrations moléculaires. La microscopie CARS est maintenant une modalité d’imagerie reconnue, en particulier pour les expériences in vivo, car elle élimine la nécessité d’utiliser des agents de contraste exogènes, et donc les problèmes liés à leur distribution, spécificité et caractère invasif. Cependant, il existe encore plusieurs obstacles à l’adoption à grande échelle de la microscopie CARS en biologie et en médecine : le coût et la complexité des systèmes actuels, les difficultés d’utilisation et d’entretient, la rigidité du mécanisme de contraste, la vitesse de syntonisation limitée et le faible nombre de méthodes d’analyse d’image adaptées. Cette thèse de doctorat vise à aller au-delà de certaines des limites actuelles de l’imagerie CARS dans l’espoir que cela encourage son adoption par un public plus large. Tout d’abord, nous avons introduit un nouveau système d’imagerie spectrale CARS ayant une vitesse de syntonisation de longueur d’onde beaucoup plus rapide que les autres techniques similaires. Ce système est basé sur un laser à fibre picoseconde synchronisé qui est à la fois robuste et portable. Il peut accéder à des lignes de vibration Raman sur une plage importante (2700–2950 cm-1) à des taux allant jusqu’à 10 000 points spectrales par seconde. Il est parfaitement adapté pour l’acquisition d’images spectrales dans les tissus épais. En second lieu, nous avons proposé une nouvelle méthode d’analyse d’images pour l’évaluation de la structure de la myéline dans des images de sections longitudinales de moelle épinière. Nous avons introduit un indicateur quantitatif sensible à l’organisation de la myéline et démontré comment il pourrait être utilisé pour étudier certaines pathologies. Enfin, nous avons développé une méthode automatisé pour la segmentation d’axones myélinisés dans des images CARS de coupes transversales de tissu nerveux. Cette méthode a été utilisée pour extraire des informations morphologique des fibres nerveuses dans des images CARS de grande échelle.<br>Optical-based microscopy techniques can sample biological specimens using many contrast mechanisms providing good sensitivity and high spatial resolution while minimally interfering with the samples. Coherent anti-Stokes Raman scattering (CARS) microscopy is a nonlinear microscopy technique based on the Raman effect. It shares common characteristics of other optical microscopy modalities with the added benefit of providing an endogenous contrast mechanism sensitive to molecular vibrations. CARS is now recognized as a great imaging modality, especially for in vivo experiments since it eliminates the need for exogenous contrast agents, and hence problems related to the delivery, specificity, and invasiveness of those markers. However, there are still several obstacles preventing the wide-scale adoption of CARS in biology and medicine: cost and complexity of current systems as well as difficulty to operate and maintain them, lack of flexibility of the contrast mechanism, low tuning speed and finally, poor accessibility to adapted image analysis methods. This doctoral thesis strives to move beyond some of the current limitations of CARS imaging in the hope that it might encourage a wider adoption of CARS as a microscopy technique. First, we introduced a new CARS spectral imaging system with vibrational tuning speed many orders of magnitude faster than other narrowband techniques. The system presented in this original contribution is based on a synchronized picosecond fibre laser that is both robust and portable. It can access Raman lines over a significant portion of the highwavenumber region (2700–2950 cm-1) at rates of up to 10,000 spectral points per second and is perfectly suitable for the acquisition of CARS spectral images in thick tissue. Secondly, we proposed a new image analysis method for the assessment of myelin health in images of longitudinal sections of spinal cord. We introduced a metric sensitive to the organization/disorganization of the myelin structure and showed how it could be used to study pathologies such as multiple sclerosis. Finally, we have developped a fully automated segmentation method specifically designed for CARS images of transverse cross sections of nerve tissue.We used our method to extract nerve fibre morphology information from large scale CARS images.
16
Noestheden, Matthew. "Towards cellular imaging with chemical and molecular specificity: Raman and coherent anti-Stokes Raman (CARS) microscopy." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27399.
Full textAbstract:
The lack of photobleaching, minimal sample heating, and high acquisition rates associated with coherent anti-Stokes Raman scattering (CARS) microscopy make it an attractive approach for the chemically specific in vivo imaging of dynamical processes. However, imaging capabilities are currently confined to classes of macromolecules as opposed to specific molecular targets. The use of cyano and deuterium functional group labels, which possess Raman modes in a spectral region devoid of endogenous cellular resonances, has the potential to surmount this limitation, enabling imaging with chemical and molecular specificity using CARS microscopy. Herein, cyano and deuterium vibrational modes have been incorporated into Raman and CARS contrast agents capable of mediating biomolecular modification. Application of this approach will be demonstrated using hepatitis C virus (HCV) RNA and two model protein systems with the end goal of investigating dynamical aspects of HCV molecular virology in real-time in vivo using CARS microscopy. The addition of exogenous CARS labels to a biomolecule can have serious structural and functional consequences that may lead to the expression of a phenotype dictated by the effects of the modification rather than the system under investigation. Therefore, the structural and functional consequences of introducing CARS labels needed to be investigated before applying cyano and deuterium modified HCV RNA and proteins to in vivo analysis using CARS microscopy.
17
Gutschank, Jörg [Verfasser]. "Implementation of coherent Raman detected electron paramagnetic resonance / Jörg Gutschank." Dortmund : Universitätsbibliothek Technische Universität Dortmund, 2005. http://d-nb.info/1011533111/34.
Full text
18
Pickup-Gerlaugh, Adam John. "Development of coherent Raman scattering microscopy for monitoring drug delivery." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12407/.
Full textAbstract:
Topical pharmaceuticals are a vitally important part of modern medicine. Currently, characterising the dermatopharmacokinetics of these drugs is very difficult, and not possible in either real-time, or with a high level of accuracy. This thesis applies three coherent Raman scattering microscopy techniques to the challenge of video-rate monitoring of a porcine skin model undergoing penetration by two different, widely used, pharmaceuticals. It was found that the data taken during these time-course experiments could be used in conjunction with a Beer-Lambert expression, and Fick’s second law, to extract valuable permeation data – namely the skin-solute partition coefficient, and diffusion coefficient – of these pharmaceuticals.
19
Camp, Charles Henry Jr. "Label-free flow cytometry using multiplex coherent anti-Stokes Raman scattering (MCARS) spectroscopy." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42733.
Full textAbstract:
Over the last 50 years, flow cytometry has evolved from a modest cell counter into an invaluable analytical tool that measures an ever-expanding variety of phenotypes. Flow cytometers interrogate passing samples with laser light and measure the elastically scattered photons to ascertain information about sample size, granularity, and basic morphology. Obtaining molecular information, however, requires the addition of exogenous fluorescent labels. These labels, although a power tool, have numerous challenges and limitations such as large emission spectra and cellular toxicity. To move beyond fluorescent labels in microscopy, a variety of techniques that probe the intrinsic Raman vibrations within a sample have been developed, such as coherent anti-Stokes Raman scattering (CARS) and Raman microspectroscopy. In this dissertation, I present the first development of a label-free flow cytometer that measures the elastically scattered photons and probes the intrinsic Raman vibrations of passing
samples using multiplex coherent anti-Stokes Raman scattering (MCARS). MCARS, a coherent Raman technique that probes a large region of the Raman spectrum simultaneously, provides rich molecularly-sensitive information. Furthermore, I present its application to sorting polymer microparticles and its use in two example biological applications: monitoring lipid bodies within cultures of Saccharomyces cerevisiae, a model yeast with numerous human homologs, and monitoring the affect of nitrogen starvation on Phaeodactylum tricornutum, a diatom, which is being genetically engineered to efficiently produce biofuels.
20
Thomas, Fabrice. "Calibrages et études applicatives de la technologie SWIFTS." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT136.
Full textAbstract:
SWIFTS (Stationary Wave Integrated Fourier Transform Spectrometer) est une nouvelle technologie innovante de spectrométrie qui permet une réduction radicale de la taille des spectromètres à Transformée de Fourier, tout en conservant, et même en améliorant leurs performances. Grâce aux avancées de l'optique intégrée et des nanotechnologies, SWIFTS repose sur une méthode de détection optique originale, sans aucune partie mobile, où des nanoplots métalliques échantillonnent directement le champ évanescent d'une onde stationnaire dans un guide d'onde.Dans cette thèse, nous proposons de présenter le cheminement complet qui a mené, en partant du concept original, au développement puis à la mise en pratique de la technologie SWIFTS. Le document illustre notamment les caractérisations optiques, les choix technologiques et les optimisations entrepris pour la réalisation de spectromètres fonctionnels dans le domaine visible et proche-infrarouge. Des procédures de calibrages novatrices et complémentaires, basées sur du multiplexage fréquentiel et sur de l'interférométrie à faible cohérence temporelle, ont été développées pour déterminer avec précision les différentes irrégularités de fabrication et de comportement de l'appareil complètement intégré. Les spectromètres calibrés permettent à présent d'aborder des applications diverses en industrie et en recherche, de la caractérisation hautes performances de lasers, à l'interrogation de capteurs fibrés à réseaux de Bragg, aux techniques de spectrométries Raman et LIBS, et de tomographie optique OCT, jusqu'aux sciences de l'Univers (géophysique, astrophysique).SWIFTS est une innovation de rupture qui, de part sa miniaturisation obtenue sans compromis avec de hautes performances d'analyse spectrale, a la capacité de faire passer la spectrométrie du stade de la mesure complexe en laboratoire à celle d'un simple composant intégré pour des applications exigeantes<br>SWIFTS (Stationary Wave Integrated Fourier Transform Spectrometer) is a new innovative technology of spectrometry that allows a drastic reduction of the size of Fourier transform spectrometers, while maintaining, and even improving their performance. With advances in integrated optics and nanotechnology, SWIFTS is based on an original method of optical detection, without any moving part, where metallic nanodots directly sample the evanescent field of a standing wave in a waveguide.In this thesis, we propose to present the complete process that led, starting from the original concept, to the development and the applications of the technology. The document illustrates the optical characterizations, the technological choices and the optimizations made for the realization of functional spectrometers in the visible and near-infrared range. Innovative and complementary procedures of calibrations, based on frequency multiplexing and low coherence interferometry, have been developed to accurately determine the various irregularities of the manufacturing and of the behavior of the integrated device. The calibrated spectrometers allow to address various applications in industry and research, such as high performance characterization of lasers, interrogation of fiber Bragg gratings sensors, Raman and LIBS spectrometry, optical coherence tomography OCT, and sciences of the Universe (geophysics, astrophysics).SWIFTS is a breakthrough innovation in spectrometry, without trade-off between miniaturization and high performance, that opens the way for product development based on the most demanding applications currently performed in research laboratories
21
Curtis, Kelly Marie. "Comparing coherent and spontaneous Raman modalities for the investigation of gastrointestinal cancers." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/27974.
Full textAbstract:
The incidence of gastrointestinal (GI) cancers has been steadily increasing in the UK since the mid 1970’s. These include cancers of the colon and oesophagus. Colon cancers have a high incidence rate, being the fourth most common cancer in the UK for both men and women. Oesophageal cancers in comparison are much rarer, however they have a poor survival rate primarily due to a late diagnosis. The key to improving survival for these cancers and many others is to detect and remove the disease at the early stages, to prevent the cancer from advancing. At present the ‘gold standard’ for diagnosis is a biopsy followed by histopathology. This technique is invasive, time consuming and highly subjective. It is therefore important to look towards non-invasive methods for early and rapid diagnosis. Optical techniques have begun to show such promise. By probing the interactions of tissues with light, diagnostic information is able to be obtained non-invasively. Techniques such as Raman spectroscopy utilise inherent molecular vibrations to extract biochemical information from tissues. Raman spectroscopy, however, is currently fundamentally limited by long acquisition times, due to the inherently weak signals produced. Using coherent Raman techniques such as coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS), the molecular vibrations are coherently driven to provide an enhancement in signal. This thesis explored spectral signatures from snap frozen oesophageal sections in the fingerprint (450 cm-1 to 1850 cm-1) and high wavenumber (2800 cm-1 to 3050 cm-1) regions using spontaneous Raman and compared with spectra from hyperspectral SRS. The diagnostic potential for each technique was assessed for four major pathology groups, normal, Barrett’s oesophagus, dysplasia and adenocarcinoma. Samples were classified using a principal component fed linear discriminant analysis (PCA-LDA) approach with a leave-one-out cross validation. Comparisons were made to haematoxylin and eosin (H&E) stained sections. Raman in the fingerprint region was found to be the most promising for diagnosis. There were minimal changes in the high wavenumber region between pathology groups which was also reflected in the SRS spectra and proved to be insufficient for classification. Further comparisons were made between spontaneous and coherent Raman techniques using frozen colon sections. The morphological and structural information available was explored using a k-means cluster analysis. Both spontaneous and coherent Raman were able to distinguish important structural features in the colon, such as the epithelial cells that form the colonic glands and surrounding connective tissue. Both are important visual markers for cancer diagnosis in the current approach. SRS demonstrated higher spatial resolution and faster acquisition times in comparison to spontaneous Raman. This work has discussed the many advantages of using coherent Raman techniques for tissue applications, but has also highlighted some of the limitations for spectral measurements, arising from the complexity of the system.
22
Blasberg, Tilo. "Coherent raman scattering for optical detection of NMR in Pr³⁺:YAIO₃ /." Zürich, 1995. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=11027.
Full text
23
Pestov, Dmitry Sergeyevich. "Detection of bacterial endospores by means of ultrafast coherent raman spectroscopy." Texas A&M University, 2008. http://hdl.handle.net/1969.1/85958.
Full textAbstract:
This work is devoted to formulation and development of a laser spectroscopic technique
for rapid detection of biohazards, such as Bacillus anthracis spores. Coherent anti-Stokes
Raman scattering (CARS) is used as an underlying process for active retrieval of
species-specific characteristics of an analyte. Vibrational modes of constituent molecules
are Raman-excited by a pair of ultrashort, femtosecond laser pulses, and then probed
through inelastic scattering of a third, time-delayed laser field.
We first employ the already known time-resolved CARS technique. We apply it
to the spectroscopy of easy-to-handle methanol-water mixtures, and then continue
building our expertise on solutions of dipicolinic acid (DPA) and its salts, which happen
to be marker molecules for bacterial spores. Various acquisition schemes are evaluated,
and the preference is given to multi-channel frequency-resolved detection, when the
whole CARS spectrum is recorded as a function of the probe pulse delay. We
demonstrate a simple detection algorithm that manages to differentiate DPA solution
from common interferents. We investigate experimentally the advantages and
disadvantages of near-resonant probing of the excited molecular coherence, and finally
observe the indicative backscattered CARS signal from DPA and NaDPA powders. The possibility of selective Raman excitation via pulse shaping of the preparation pulses is
also demonstrated.
The analysis of time-resolved CARS experiments on powders and B. subtilis
spores, a harmless surrogate for B. anthracis, facilitates the formulation of a new
approach, where we take full advantage of the multi-channel frequency-resolved
acquisition and spectrally discriminate the Raman-resonant CARS signal from the
background due to other instantaneous four-wave mixing (FWM) processes. Using
narrowband probing, we decrease the magnitude of the nonresonant FWM, which is
further suppressed by the timing of the laser pulses. The devised technique, referred to as
hybrid CARS, leads to a single-shot detection of as few as 104 bacterial spores, bringing
CARS spectroscopy to the forefront of potential candidates for real-time biohazard
detection. It also gives promise to many other applications of CARS, hindered so far by
the presence of the overwhelming nonresonant FWM background, mentioned above.
24
Barlow, Aaron M. "Spectral Distortions & Enhancements In Coherent Anti-Stokes Raman Scattering Hyperspectroscopy." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32388.
Full textAbstract:
Coherent anti-Stokes Raman scattering microscopy is a versatile technique for label-free imaging and spectroscopy of systems of biophysical interest. Due to the coherent nature of the generated signals, CARS images and spectra can often be difficult to interpret. In this thesis, we document how distortions and enhancements can be produced in CARS hyperspectroscopy as a result of the instrument, geometrical optical effects, or unique molecular states, and discuss how these effects may be suppressed or exploited in various CARS applications.
25
Atherton, Kathryn Jane. "Coherent Raman studies of optical nonlinearities in conjugated molecules and polymers." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298790.
Full text
26
Trindell, Daniel Lloyd. "Coherent Anti-Stokes Raman Scattering (CARS) studies of metal halide vapours." Thesis, University of Sheffield, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364333.
Full text
27
Porter, Fiona M. "A study of temperature measurement using Coherent Anti-Stokes Raman Spectroscopy." Thesis, University of Surrey, 1985. http://epubs.surrey.ac.uk/847913/.
Full textAbstract:
The aim of this work is to increase the applicability of Coherent Anti-Stokes Raman Spectroscopy (CARS) to temperature measurement in practical devices. Particular emphasis is placed on combustion thermometry and high pressure steam systems are also considered. A study is made of the temperature measurement accuracy attainable in the range 290 to 1050 K, using broadband CARS. Accuracies of 1 - 2% are attained, and laser cross coherence effects are found to be important. The determination of temperature probability density functions is of great importance to combustion science. Their measurement using single shot CARS requires the analysis of very large numbers of spectra. A study is made of fast methods of data analysis and the temperature measurement precision attainable using them. A very rapid data analysis method suitable for use in fluctuating temperature, pressure and concentration environments is developed. The temperature precision attainable using CARS is limited by CARS signal noise. For systems with high temperature fluctuations, detector counting statistics are found to make a dominant contribution to this. The spread in measured temperature probability density function width due to signal noise is characterised for the CARS system used, as a function of CARS signal strength for the temperature range 290 to 1050 K. A fast CARS signal analysis method is applied to map temperatures and temperature fluctuations in the flame zone of a turbulent oil spray furnace. The temperature measurements are compared with Discrete Droplet and Continuous Droplet oil spray model predictions (Stopford, 1984) with good agreement, particularly in the former case. In the post flame region, where turbulent fluctuations are less severe, averaged measurements of H[2]O concentrations were made.
28
Smith, Lowenna. "Magneto-optical spectroscopy and coherent Raman studies of dilute magnetic semiconductors." Thesis, University of Bath, 2007. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439273.
Full text
29
Lee, Martin. "Imaging intra-cellular wear debris with coherent anti-Stokes Raman scattering spectroscopy." Thesis, University of Edinburgh, 2013. http://hdl.handle.net/1842/7735.
Full textAbstract:
Aseptic loosening of artificial joints is caused by an osteolytic reaction to wear debris mediated by macrophages and other cells. Imaging these wear particles within cells can be a key process in understanding particle-cell interactions. However, the compounds used in surgical implants are not easily visualised as no tagging molecule can be added without altering the properties of the material. We were interested in using a label free optical technique known as coherent anti-Stokes Raman scattering spectroscopy (CARS) to image these particles in cells. In this thesis we studied how to use CARS to image physiologically relevant wear particles within cells. We characterised the responses from our CARS system and found them to be in good agreement to the Raman spectra we obtained for the same materials. We showed that the forward scattered CARS signal was consistently larger than the backwards scattered signal for the same size particles, and also generated a larger contrast, especially between sub-micron sized particles and the non-resonant background. Wear particles of polyethylene isolated from a pin-on-plate wear simulator were shown to be in a similar size range to those retrieved from revision tissue. When incubated in our model macrophage cells we were able to image areas of CARS signal that indicated the location of these particles in the cell. Furthermore, using multiple CARS images taken at different Raman resonances we were able to distinguish between three different polymeric compounds added to cells, showing the specificity of the technique. The inherent 3D sectioning capabilities of multiphoton microscopy were used to generate projected images of the cells and contents, as well as estimating the particle loads within cells. These results show that CARS could be an important tool in imaging intra-cellular polyethylene and characterising the interactions of wear particles with cells and the surrounding tissue.
30
Wang, Yingying. "Quantum-fluctuation-initiated coherent Raman comb in hydrogen-filled hollow-core photonic crystal fibre." Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.545332.
Full textAbstract:
This thesis explores the generation and the coherence properties of Raman frequency combs that are initiated from vacuum fluctuations using hydrogen-filled hollow-core photonic crystal fibre (HC-PCF). The motivation is to explore a novel route for generating attosecond pulses and waveform synthesis. To this end, work has been undertaken in the design and fabrication of HC-PCF, in the generation of Raman comb with a compact set-up and finally in an experimental demonstration of the mutual coherence between the comb spectral components. Here, the well-established photonic bandgap (PBG) HC-PCF is further developed. Surface mode spectral positions are controlled by chemical etching technique, and a single piece of fibre with two robust bandgaps is fabricated. Furthermore, the second established class of HC-PCF; namely large-pitch Kagome-lattice HC-PCF, has experienced challenging developments. This led to the fabrication of a hypocycloid-core seven-cell Kagome HC-PCF with comparable attenuation value to that of PBG HC-PCF while offering much larger bandwidth. Using the fabricated HC-PCF, different Raman frequency comb systems are developed. In addition to the previously-generated multi-octave Raman frequency comb from a large 1064 nm Nd:YAG Q-switch laser, several more compact version of Raman comb sources have been developed, including one whose lines lay in the visible and UV for applications in forensics and biomedicine. The Raman frequency comb generated inside a length of hydrogen-filled HC-PCF is further investigated by studying the coherence of the Raman lines. Despite of vacuum-fluctuation-initiation, it is demonstrated that the comb has self- and mutualcoherence properties within each single shot, bringing thus the possibility of generating attosecond pulses with non-classical properties.
31
Xu, Xiaoji. "New methods of coherent anti-Stokes Raman spectroscopy based on broadband pulses." Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/8445.
Full textAbstract:
The research work of this Ph.D. thesis is centered on coherent anti-Stokes Raman spectroscopy (CARS) with broad band coherent pulses. After a mathematical derivation of the formula that is responsible for CARS, four new approaches were proposed. The first method of Noise-autocorrelation spectroscopy with coherent Raman scattering utilizes spectral noise to reveal vibrational level spacings through autocorrelation. Its variation of Narrowband spectroscopy by all-optical correlation of broadband pulses, uses the technique of optical processing based on noisy probe pulse of special shape to obtain high resolution CARS spectra. The method of complete characterization of molecular vibration, can measure the phase of laser induced vibration through amplitude and phase retrieval on a time-frequency spectrogram. It is also a high resolution method. The final method Background free coherent Raman spectroscopy by detecting spectral phase of molecular vibrations is the spectroscopic application of detected spectral phase of laser induced vibration.
32
Ocampo, Minette C. "Construction, Optimization and Testing of a Coherent Anti-Stokes Raman Scattering Microscope." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1300727934.
Full text
33
Karuna, Arnica. "Applications of coherent anti-Stokes Raman scattering (CARS) microscopy to cell biology." Thesis, Cardiff University, 2016. http://orca.cf.ac.uk/94088/.
Full textAbstract:
Traditionally, many advances in the field of biology have been driven by optical microscopy based techniques which reveal morphological information about the samples under study [1, 2, 3, 4]. The scope of the applications of these methods is limited due to the lack of contrast from most biological materials (cells and tissues) which are transparent to visible light. The introduction of extraneous materials (such as fluorescent quantum dots or other fluorescent proteins/labels) with affinity towards certain sub-cellular components which are then imaged, has emerged as a popular and powerful method to image biological materials. Fluorescence microscopy using visible wavelengths in its simplest application includes the identification and imaging of interesting features of a sample which are fluorescently labelled in a structurally/ chemically specific way. In more recent developments, fluorescence lifetimes have been imaged. Fluorescence based techniques can also be applied to track protein dynamics or drug delivery in live samples. Despite the benefits of imaging samples with labels, and a host of associated applications, the issues of photobleaching and induced phototoxicity remain. Another very important aspect which gains relevance in live sample imaging is that the system dynamics may be influenced by the introduction of fluorescent labels. Spectroscopy techniques, which rely on the material resonances are chemically specific, sensitive, and if combined with microscopy, bridge the gap between non-invasive imaging and fluorescence microscopy. Instead of an extraneous label, the contrast generated originates from molecular transitions of the chemical species in the sample. Coherent Raman scattering (CRS) based techniques rely on the chemical contrast generated due to molecular vibrations and have been applied to biology [5]. One CRS technique, stimulated Raman scattering (SRS) has been used to distinguish between the macromolecular constituents of cells [6, 7] and tissues [8]. Additionally, quantitative hyperspectral SRS has been demonstrated in polymer and lipid mixtures [6]. Another type of CRS, coherent anti-Stokes Raman scattering (CARS) [9] was reported in 1965, nearly half a decade before SRS. However, due to difficulties in implementation, CARS was not readily put to application. Since its revival in 1999 [10], CARS has emerged as a label-free, chemically specific microscopy technique and has been applied to image various biological materials [11, 12]. In addition to the studies of lipid rich samples [13, 14], spectral differences between the cytosol and the nucleus have been reported using CARS microscopy [15, 16]. However, none of the previous works in this field present full 3D hyperspectral data, or make quantitative volumetric estimates of the various chemical components present in the sample. With respect to biomedical/biochemical application based studies, literature suffers from a paucity of examples investigating the effects of drugs on biological materials using CARS microscopy. This project aims to overcome these shortcomings. In this work, CARS microscopy is applied to single cells (osteosarcoma, U-2OS which are lipid poor due to their functional profile) with volumetric quantitative analysis to determine the absolute masses of the component species. For the first time in our knowledge, full 3D hyperspectral data has been acquired and analyzed. Correlative fluorescence imaging to ascertain the origin of various components of the cells as imaged with CARS was also performed. Furthermore, reports of no observed (with CARS) correlation in protein content in the intranuclear region with the mitotic stage in cells one publication [16] have been disproved, shown in this thesis. Osteosarcoma is a rare type of cancer, most commonly diagnosed in children and adolescents. However, due to its rarity, it is not well researched. The usual line of treatment includes surgery followed by chemotherapy, of which Taxol (microtubule stabilizer) and ICRF-193 (topoisomerase II poison) form an important part. The effects of these drugs on cells are often investigated in literature using a range of techniques, of which, the most non-invasive one is chemically non-specific optical microscopy [17, 18]. Among the chemically specific methods used to perform such studies, flow cytometry [19, 20, 21] is one of the most commonly employed; and the most invasive methods, also in widespread use, are Western blotting and gel electrophoresis [22]. This means that in the best case scenario, we can perform optical microscopy on the cells with no chemical specificity or sensitivity, or sacrifice non-invasiveness for chemical information. Identifying a need for label-free methods to study the effects of these drugs, we applied CARS microscopy to study the effects of Taxol and ICRF-193 on U-2OS cells. This was done to determine whether CARS microscopy is suitable for population phenotyping and profiling the effects of anticancer drugs over a period of time, following treatment. Also for the first time, in this project, CARS microscopy has been demonstrated with chemical specificity and sensitivity on structurally and functionally multicellular 3D assemblies, organoids. In the past, other groups have reported studies on organoids, their metabolism and drug interactions using fluorescence microscopy [23, 24, 25], with the already mentioned shortcomings and pitfalls of photodamage and photobleaching. This thesis is structured into five chapters. The required background is given in the first two chapters. The first chapter introduces optical spectroscopy with emphasis on CARS, including a discussion of the theory and the various implementations of CARS microscopy. The second chapter contains the biology background in cells and cell division requisite for this project. An overview of the current state of the art in imaging techniques is also given. The set-up and analysis techniques used to acquire and analyze the data presented in this work are described in the third chapter, along with a characterization of the effects of the imaging optics and the sample’s refractive index on the analysis method and the quantitative calculations, using polystyrene and polymethymethacrylate beads of different sizes. The next two chapters describe the applications of CARS microscopy to fixed U- 2OS cells and organoids. In chapter four, the results of CARS imaging and spectral analysis of U-2OS cells correlated with two-photon fluorescence are shown. Furthermore, applications of CARS to study the effects of two kinds of anti-cancer drugs i.e, Taxol and ICRF-193 on U-2OS cells are demonstrated. Additionally, a side project not related to CARS microscopy, but presenting a simple method to quantitatively investigate the number of eGFP molecules attached to cyc-B, across the cell cycle is also described in this chapter. Chapter five demonstrates the suitability of CARS microscopy to image higher levels of biological organization, specifically organoids which are miniature lab grown 3D models of organs. The summary and outlook of this project are given in the last chapter, which is followed by the Appendices including additional detailed information referenced in the thesis. All 3D data are available as videos in the data DOI related to this thesis.
34
Bourdon, Pierre. "Etude d'un oscillateur parametrique optique injecte et de son application a la spectroscopie raman coherente." Palaiseau, Ecole polytechnique, 1995. http://www.theses.fr/1995EPXX0027.
Full textAbstract:
La diffusion raman anti-stokes coherente (drasc) est une methode non-intrusive de thermometrie et de dosimetrie de la phase gazeuse qui met en uvre plusieurs lasers impulsionnels, dont un laser accordable. L'utilisation de lasers a solides accordables permet d'envisager d'ameliorer les performances des bancs de mesure par drasc. Parmi les differentes solutions accordables a base de lasers a solides, l'utilisation d'un oscillateur parametrique optique (opo) nanoseconde pompe par un laser nd: yag triple et utilisant un cristal de beta-borate de barium (bbo) s'avere optimale pour la drasc. Cet opo est une source permettant de couvrir tout le domaine visible ainsi que le proche infrarouge, et dont les proprietes energetiques et spectrales permettent l'utilisation pour la drasc, a condition de le rendre simplement resonnant. Cette configuration necessite l'utilisation de l'accord de phase non-colineaire, dont une etude detaillee mene a des proprietes spectrales originales de l'opo. Afin d'obtenir une haute resolution des spectres raman, l'opo est ensuite affine spectralement par injection optique avec des diodes laser. En particulier, l'utilisation d'une diode laser en cavite externe permet de rendre l'opo monomode longitudinal tout en lui conservant une part d'accordabilite. Cette source monomode accordable permet d'obtenir par drasc des profils bien resolus de la raie q(5) de l'hydrogene moleculaire, a differentes pressions et temperatures
35
Zhi, Miaochan. "Broadband coherent light generation in Raman-active crystals driven by femtosecond laser fields." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2578.
Full text
36
Iqbal, Md Asif. "Advanced Raman amplification techniques for high capacity and broadband coherent optical transmission systems." Thesis, Aston University, 2018. http://publications.aston.ac.uk/37651/.
Full textAbstract:
This thesis presents a detailed study of different advanced Raman fibre laser (RFL) based amplification schemes and the development of novel broadband distributed and discrete Raman amplifiers in order to improve the transmission performance of modern high capacity, long-haul coherent optical systems. The numerical modelling of different Raman amplifier techniques including power distribution of signal, pump and noise components, RIN transfer from pump to signal, broadband gain optimization and so on have been described in details. The RIN and noise performances of RFL based distributed Raman amplifiers (DRAs) with different span lengths, forward pump powers and input reflection levels have been characterized experimentally. It has been shown through coherent transmission experiment that, in order to improve pump power efficiency, a low level of input reflection up to ~10% can be allowed without increasing the Q factor penalty > 1dB due to additional signal RIN penalty. A novel broadband (>10nm) first order Raman pump is developed for use as a forward pump in long-haul transmission experiment. Significant signal RIN mitigation up to 10dB compared with conventional low RIN, narrowband sources was obtained for bidirectional DRA schemes. Long-haul coherent transmission experiments with 10×120Gb/s DP-QPSK system were carried out in are circulating loop setup using the proposed broadband pump in bidirectional and backward only pumping configurations. The maximum transmission reach up to ~8330km was reported with first order broadband pumped bidirectional DRA, with transmission reach extensions of 1250km and1667km compared with conventional backward only and first order semiconductor pumped bidirectional pumping scheme respectively. Finally, a novel design of bidirectional broadband distributed DRA is proposed to reduce the noise figure tilt and improve the WDM transmission performances. Furthermore, broadband discrete Raman amplifier schemes in dual stage configuration are also shown for high gain, high output power, low noise and low nonlinear performances.
37
Di, Napoli Claudia. "Label-free multiphoton microscopy of intracellular lipids using Coherent anti-Stokes Raman Scattering (CARS)." Thesis, Cardiff University, 2014. http://orca.cf.ac.uk/60484/.
Full textAbstract:
Coherent Antistokes Raman Scattering (CARS) microscopy has emerged in the last decade as a powerful multiphoton microscopy technique to rapidly image lipid droplets (LDs) label-free with intrinsic three-dimensional spatial resolution in cells. In this thesis I investigate and compare the ability of hyperspectral CARS and dual-frequency/differential CARS (D-CARS) to enable the chemical specificity required to distinguish lipids of different chemical composition. In hyperspectral CARS a series of spatially-resolved images are acquired over a frequency range thus proving high chemical specificity. In D-CARS two vibrational frequencies are simultaneously excited and probed, and the resulting sum and difference CARS intensities are detected by a fast and efficient single photomultiplier. This results in a higher image speed than hyperspectral CARS and in an improved image contrast against the nonresonant CARS background with a straightforward data analysis. D-CARS and hyperspectral CARS techniques were applied to LDs in model and cellular systems. In model systems made by agarose gel, droplets of pure lipids with different degree of unsaturation (number of carbon-carbon double bonds in the fatty acyl chain) were used as test sample to compare Raman spectra with CARS spectra, and measure D-CARS images at specific chemically-selective wavenumbers. Building from this knowledge, cytosolic droplets induced by loading fatty acids to the culture media of human adipose-derived stem cells (ADSCs) were distinguished in composition both in fixed cells and in living cells during differentiation into adipocytes. Furthermore, the application of a in-house developed Hyperspectral Image Analysis (HIA) software on hyperspectral data provided spatial distributions and absolute concentrations for the chemical components of the investigated specimens. In particular quantitative information was extracted about the concentration of pure neutral lipid components within cytosolic LDs, and changes over time were inferred in living ADSCs according to the type of pure fatty acid added to the culture media.
38
Hung, Yi-chen Hung. "Characterization of Nonequilibrium Reacting Molecular Plasmas and Flames using Coherent Anti-Stokes Raman Spectroscopy." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1531930166735281.
Full text
39
Simon, Russell James. "The use of Coherent Anti-Stokes Raman Spectroscopy as a diagnostic technique for studying the hydrogenation of carbon moxide {i.e. monoxide} in a tube-wall reactor." Thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/23441.
Full text
40
Gomes, da Costa Stefan [Verfasser], and Jörg [Akademischer Betreuer] Wrachtrup. "Hyperspectral coherent anti-Stokes Raman scattering (CARS) imaging / Stefan Gomes da Costa ; Betreuer: Jörg Wrachtrup." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2019. http://d-nb.info/1203128673/34.
Full text
41
Massoud, Mouhannad. "Experimental characterization of heat transfer in nanostructured silicon-based materials." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI063/document.
Full textAbstract:
Ce mémoire de thèse aborde la caractérisation expérimentale du transfert thermique à l’échelle nanométrique dans des matériaux compatibles avec les procédés de la micro-électronique. Pour cela deux techniques de caractérisation sont appliquées chacune à deux différents systèmes, le silicium mésoporeux irradié et les membranes de silicium suspendues. La première technique de caractérisation est la thermométrie micro-Raman. La puissance du laser chauffe l'échantillon exposé. La détermination de la conductivité thermique nécessite la modélisation de la source de chaleur par la méthode des éléments finis. Dans les cas considérés la modélisation de la source de chaleur repose sur différents paramètres qui doivent être soigneusement déterminés. La seconde technique de caractérisation est la microscopie à sonde locale (d’acronyme anglais SThM), basée sur le principe de la microscopie à force atomique (d’acronyme anglais AFM). Utilisée en mode actif, la sonde AFM est remplacée par une sonde résistive de type Wollaston qui est chauffée par effet Joule. Utilisée en mode AFM contact, cette technique permet une excitation thermique locale du matériau étudié. La détermination de la conductivité thermique nécessite l'analyse de la réponse thermique de la sonde au moyen d'échantillons d'étalonnage et également via la modélisation dans le cas des géométries complexes. L'effet de la position de la pointe sur le transfert de chaleur entre la pointe et l'échantillon est étudié. Une nouvelle méthode de découplage entre le transfert de chaleur entre la pointe et l'échantillon, respectivement à travers l'air et au contact, est proposée pour la détermination de la conductivité thermique des géométries complexes. Les résultats obtenus avec les deux techniques pour les échantillons de silicium mésoporeux irradiés à l’aide d’ions lourds dans le régime électronique sont en bon accord. Ils montrent la dégradation de la conductivité thermique du silicium mésoporeux suite à une augmentation dans la phase d’amorphe lorsque la dose d’irradiation croît. Les résultats obtenus sur les membranes de silicium suspendues montrent une réduction de la conductivité thermique de plus de 50 % par rapport au silicium massif. Lorsque la membrane est perforée périodiquement afin de réaliser une structure phononique de période inférieure à 100 nm, cette réduction est approximativement d’un ordre de grandeur. Un chapitre introduisant un matériau prometteur à base de silicium pour observer des effets de cohérence phononique conclut le manuscrit<br>This PhD thesis deals with the experimental characterization of heat transfer at the nanoscale in materials compatible with microelectronic processes. Two characterization techniques are applied to two different systems, irradiated mesoporous silicon and suspended silicon membranes. The first characterization technique is micro-Raman thermometry. The laser power heats up the exposed sample. The determination of the thermal conductivity requires the modeling of the heat source using finite element simulations. The modeling of the heat source relies on different parameters that should be carefully determined. The second characterization technique is Scanning Thermal Microscopy (SThM), an Atomic Force Microscopy (AFM)-based technique. Operated in its active mode, the AFM probe is replaced by a resistive Wollaston probe that is heated by Joule heating. Used in AFM contact mode, this technique allows a local thermal excitation of the studied material. The determination of the thermal conductivity requires the analysis of the thermal response of the probe using calibration samples and modeling when dealing with complicated geometries. The effect of the tip position on heat transfer between the tip and the sample is studied. A new method decoupling the heat transfer between the tip and the sample, at the contact and through air, is proposed for determining the thermal conductivity of complicated geometries. The results obtained from the two techniques on irradiated mesoporous silicon samples using heavy ions in the electronic regime are in good agreement. They show a degradation of the thermal conductivity of mesoporous silicon due to the increase in the amorphous phase while increasing the ion fluence. The results obtained on suspended silicon membrane strips show a decrease in the thermal conductivity of more than 50 % in comparison to bulk silicon. When perforated into a phononic structure of sub-100 nm period, the membrane thermal conductivity is about one order of magnitude lower than the bulk. A chapter introducing a promising silicon-based material for the evidence of phonon coherence concludes the manuscript
42
THUET, JEAN-MICHEL. "Effet des transferts rotationnels d'etat a etat et des echanges d'energie cinetique sur les profils de diffusion raman coherente." Besançon, 1993. http://www.theses.fr/1993BESA2021.
Full textAbstract:
Le developpement des diagnostics des milieux en combustion, par des techniques de diffusion de la lumiere resolues spatiotemporellement necessite une connaissance de plus en plus precise de leur signature spectrale. Le calcul de cette signature requiert une excellente maitrise des mecanismes collisionnels. De la precision de ces calculs depend en effet celle de la determination de la temperature et de la concentration locales de ces milieux. Les collisions entrainent des transferts d'energie entre les divers etats rotationnels, lesquels doivent etre decrits a partir de modeles physiques fiables. C'est au developpement de tels modeles que cette these est consacree. De nouveaux tests ont ete mis en uvre, soit en utilisant les mesures des temps de relaxation de l'energie et du moment cinetique rotationnels, soit de facon plus fine, celle des taux de transferts d'etat-a-etat. La derniere partie du travail est consacree a des mecanismes plus specifiquement lies a la molecule d'hydrogene, dont le role dans la nouvelle generation des moteurs fusees cryogeniques est crucial. L'un des mecanismes concernant l'echange d'energie cinetique a des consequences singulieres qui ont ete etudiees en detail. Ce travail ouvre la voie a des applications au diagnostic de la reaction de formation de l'eau en cours de realisation
43
Hadj-Bachir, Mokrane. "Laser à rayons X ultra-compact Raman XFEL." Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0400/document.
Full textAbstract:
L’obtention d’un Laser à Électrons Libres X (LEL-X) compact est un objectif majeur pour le développement des lasers. Plusieurs schémas prometteurs de LEL-X ont été proposés en utilisant à la fois l’accélération d’électrons dans les plasmas et des onduleurs optiques en régime Compton ou Compton inverse. Nous avons proposé un nouveau concept de LEL-X compact baptisé Raman XFEL, en combinant la physique des LEL en régime Compton, des lasers XUV conventionnels basés sur l’interaction laser plasma, et de l’optique non-linéaire. Nous étudions dans cette thèse les étapes préalables pour déclencher un effet laser à rayons X lors de l’interaction entre un paquet d’électrons libres relativistes et un réseau optique créé par l’interférence transverse de deux impulsions laser intenses. Dans cet objectif j’ai développé un code particulaire baptisé RELIC. Les études menées avec le code RELIC nous ont permis d’étudier la dynamique d’électrons relativistes et les processus d’injection du paquet d’électrons dans le réseau optique. Grâce à RELIC, nous avons distingué de nouveaux régimes d’interaction en fonction des paramètres du paquet d’électrons, ainsi que de la géométrie du réseau optique. Ces études ont été appliquées à l’amplification du rayonnement X et appuyées par des simulations PIC. RELIC a également permis de modéliser et d’analyser la première expérience réalisée en octobre 2015 sur l’installation laser ’Salle Jaune’ au Laboratoire d’Optique Appliquée (LOA). Cette première expérience a été une étape très importante pour la validation des modèles théoriques, et pour la réalisation future d’un laser à électrons libre X Raman<br>The quest for a compact X-ray laser has long been a major objective of laser science. Several schemes using optical undulators are currently considered, in order to trigger the amplification of back scattered radiation, in Compton or inverse Compton regime. We have proposed a new concept of compact XFEL based on a combination between the physics of free electron lasers, of laser-plasma interactions, and of nonlinear optics. In this thesis, we study the necessary steps to trigger a X-ray laser during the interaction between a free relativistic electron bunch and an optical lattice created by the interference of two intense transverse laser pulses. For this purpose I developed a particular tracking code dubbed RELIC. RELIC allowed us to study the dynamics and injection process of a bunch of relativistic electrons into the optical lattice. Thanks to RELIC, we distinguished several interaction regimes depending on the relativistic electron bunch parameters, and on those of the optical lattice and its geometry. These studies are applied to the X ray amplification and supported by PIC simulations. RELIC also allowed us to model and analyze the first experiment conducted in october 2015 on the ”Salle Jaune” laser facility at LOA. This first experiment was very important to validate our theoretical models, and should prove to be an essential milestone for the development of a Raman X-ray free electron laser
44
Hanna, Sherif Fayez. "Electronic resonance enhanced coherent anti-Stokes Raman scattering technique for detection of combustion species and biological molecules." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4379.
Full textAbstract:
The application of electronic-resonance enhanced (ERE) coherent anti-Stokes
Raman scattering (CARS) for the detection of nitric oxide (NO) and acetylene (C2H2) is
experimentally demonstrated and the effects of various parameters on the ERE CARS
signal investigated. In addition, the detection of dipicolinic acid (DPA) using âÂÂnormalâÂÂ
CARS is demonstrated.
For NO detection, the frequency difference between a visible Raman pump beam
and Stokes beam is tuned to a vibrational Q-branch Raman resonance of the No
molecule to create a Raman polarization in the medium. The second pump beam is tuned
into resonance with the rotational transitions in the (1,0) band of the A2ã+-X2ÃÂ
electronic transition at 236 nm, and the CARS signal is thus resonant with transitions in
the (0,0) band. A NO gas cell was used for the experiment to detect NO at various
pressure levels. A significant resonant enhancement of the NO CARS signal was
observed and good agreement between calculated and experimental data was obtained.
For C2H2 detection, ERE CARS experiments were performed in a roomtemperature
gas cell using mixtures of 5000 ppm C2H2 in N2. Visible pump and Stokes beams were used, with the frequency difference between the pump and Stokes tuned to
the 1974 cm-1 ÃÂ
2 Raman transition of C2H2. An ultraviolet probe beam with the
wavelengths ranging from 232 nm to 242 nm is scattered from the induced Raman
polarization to generate the ERE CARS signal. The effects of probe wavelength and
pressure on signal generation are discussed.
CARS was used to detect the 998 cm-1 vibrational Raman transition from a
sample of polycrystalline DPA. The transition is the breathing ring vibration in the
pyridine ring structure in the DPA molecule. The DPA 998 cm-1 transition is detected
with excellent signal-to-noise ratio and the full-width-at-half-maximum is very narrow,
approximately 4 cm-1.
45
Abdolvand, Amir [Verfasser], and Philip St J. [Akademischer Betreuer] Russell. "Coherent Raman Interaction in Gas-Filled Hollow-Core Photonic Crystal Fibers / Amir Abdolvand. Betreuer: Philip St.J. Russell." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2011. http://d-nb.info/1016377207/34.
Full text
46
Pilger, Christian [Verfasser]. "Development of novel Optics and Analysis Tools for enhancing Biomedical Imaging by Coherent Raman Scattering / Christian Pilger." Bielefeld : Universitätsbibliothek Bielefeld, 2019. http://d-nb.info/1192911008/34.
Full text
47
Prince, Benjamin Douglas. "Development and application of a hybrid femtosecond/picosecond coherent Raman probe designed for study of excited state systems." [Ames, Iowa : Iowa State University], 2008.
Find full text
48
Hehl, Gregor F. M. [Verfasser], and Jörg [Akademischer Betreuer] Wrachtrup. "Quantitative coherent anti-Stokes Raman scattering micro-spectroscopy : theory and applications / Gregor F. M. Hehl ; Betreuer: Jörg Wrachtrup." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2016. http://d-nb.info/1118369955/34.
Full text
49
Chen, Xueqin. "Human skin investigations using nonlinear spectroscopy and microscopy." Thesis, Ecole centrale de Marseille, 2014. http://www.theses.fr/2014ECDM0014/document.
Full textAbstract:
La peau est un organe qui enveloppe le corps, elle est une barrière naturelle importante et efficace contre différents envahisseurs. Pour le traitement des maladies dermatologiques ainsi que dans l'industrie cosmétique, les applications topiques sur la peau sont largement utilisées. Ainsi beaucoup d'efforts ont été investis dans la recherche sur la peau visant à comprendre l'absorption moléculaire et les mécanismes rendant efficace la pénétration. Cependant, il reste difficile d'obtenir une visualisation 3D de haute résolution combinée à une information chimique- ment spécifique et quantitative dans la recherche sur la peau. La spectroscopie et la microscopie non-linéaire, incluant la fluorescence excitée à 2-photon (TPEF), la diffusion Raman spontanée, la diffusion Raman cohérente anti-Stokes (CARS) et la diffusion Raman stimulée (SRS), sont introduits dans ce travail pour l'identification sans ambiguïté de la morphologique de la peau et la détection de molécules appliquées de façon topique. Plusieurs méthodes quantitatives basées sur la spectroscopie et la microscopie non-linéaire sont proposées pour l'analyse chimique en3D sur la peau artificielle, ex vivo et in vivo sur la peau humaine. De plus, afin de s'adapter aux applications cliniques à venir, un design endoscopique est étudié pour permettre l'imagerie non-linéaires dans les endoscopes flexibles<br>Skin is an organ that envelops the entire body, acts as a pivotal, efficient natural barrier to- wards various invaders. For the treatment of major dermatological diseases and in the cosmetic industry, topical applications on skin are widely used, thus many efforts in skin research have been aimed at understanding detailed molecular absorption and efficient penetration mechanisms. However, it remains difficult to obtain high-resolution visualization in 3D together with chemical selectivity and quantification in skin research. Nonlinear spectroscopy and microscopy, including two-photon excited fluorescence (TPEF), spontaneous Raman scattering, coherent anti-Stokes Raman scattering (CARS) and stimulated Raman scattering (SRS), are introduced in this work for unambiguous skin morphological identification and topical applied molecules detection. Sev- eral quantitative methods based on nonlinear spectroscopy and microscopy are designed for 3D chemical analysis in reconstructed skin, ex vivo and in vivo on human skin. Furthermore, to adapt to forthcoming clinical applications, an endoscopic design is investigated to bring nonlin- ear imaging in flexible endoscopes
50
Ziemieńczuk, Marta [Verfasser], and Philip [Akademischer Betreuer] Russell. "Coherent Gas-Laser Interactions via Stimulated Raman Scattering in Hollow-Core Photonic Crystal Fibers / Marta Ziemieńczuk. Betreuer: Philip Russell." Erlangen : Universitätsbibliothek der Universität Erlangen-Nürnberg, 2012. http://d-nb.info/1023597489/34.
Full text