Relevant bibliographies by topics / Multi-Photon microscope

Academic literature on the topic 'Multi-Photon microscope'

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Published: 7 April 2023

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Journal articles on the topic "Multi-Photon microscope"

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Piston, David W. "Multi-Photon Excitation Microscopy: An Old Idea in Quantum Theory Applied to Modern Scientific Problems." Microscopy and Microanalysis 6, S2 (August 2000): 1180–81. http://dx.doi.org/10.1017/s1431927600038393.

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Multi-photon excitation microscopy provides attractive advantages over confocal microscopy for three-dimensionalry resolved fluorescence imaging and photochemistry. The most commonly used type of multi-photon excitation is two-photon excitation where simultaneous absorption of two photons leads to a single quantitized event. The powerful advantages of using two-photon excitation microscopy arise from the basic physical principle that the absorption depends on the square of the excitation intensity. In practice, two-photon excitation is generated by focusing a single pulsed laser through the microscope. As the laser beam is focused, the photons become more crowded, but the only place at which they are crowded enough to generate an appreciable amount of two-photon excitation is at the focus. Above and below the focus, the photon density is not high enough for two of them to interact with a single fluorophore at the same time. This dramatic difference between confocal and two-photon excitation microscopy is shown in Fig. 1.
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van Hook, Lee. "Entangled Microscopy." Microscopy Today 7, no. 3 (April 1999): 6–7. http://dx.doi.org/10.1017/s1551929500064038.

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The major factor in light microscopy limiting resolution in practice is not so much the wavelength of light and the resolving power of microscope optics, but the scattering of iight by the specimen. This extraneous scattered light interferes with the light used to image the specimen, effectively reducing the contrast of the imaging light and causing other annoying problems, There have been several inventions dedicated to solving this problem: various forms of interference-based microscopies, confocal microscopy, and most recently, multi-photon confocal microscopy.
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Jason Kirk. "Beyond the Hype - Is 2-Photon Microscopy Right for You?" Microscopy Today 11, no. 2 (April 2003): 26–29. http://dx.doi.org/10.1017/s1551929500052469.

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Confocal microscopes have come a long way in the past decade. Not only are they more stable and easier to use than ever before, but their cost has dropped enough that multi-user facilities are finding competition from individual labs using the new breed of "personal" confocals. In fact it has, in some cases, become the de facto standard for fluorescence imaging regardless of whether the user actually has requirements for it or not.But, researchers always have an ear out for something better. Enter 2-photon microscopy (2PLSM). The “bigger & badder” cousin of the confocal microscope has become a new weapon in the arsenal of a microscopy industry that caters to researchers who can't wait to fill their labs with the latest and greatest imaging systems. Advertised by the industry and researchers alike as a technique that seems to solve most of the problems that plague confocal, “2-photon” has become the new buzzword in the vocabulary of researchers eager to enhance their fluorescence applications.
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Denk, Winfried. "Multi-Photon Microscopy, High Resolution Imaging Deep in Strongly Scattering Specimens." Microscopy and Microanalysis 3, S2 (August 1997): 301–2. http://dx.doi.org/10.1017/s1431927600008394.

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Imaging small structures substantially below the tissue surface in living specimens poses special challenges mainly because light is scattered by ever present refractive index inhomogeneities. Confocal microscoy removes the blurring caused by scattered and out-of-focus light but does so only at the expense of photodynamic damage that is often unacceptable when observing live specimens.Multi-photon absorption microscopy[l] solves these problems because excitation is virtually limited to the focal plane. Out-of-focus photobleaching and photodamage are therefore eliminated. In scattering samples substantial improvements accrue even for the focal plane because, different from confocal microscopy, where only ballistic fluorescenc photons can be used, in the multi-photon microscope scattered photons can be utilized in addition [2-4], provided whole-field detection is used[5].Many questions in the study of the nervous system require the investigation of intact portions of neural tissue in order to preserve the multiply branched processes of neurons, often extending over hundreds of microns, together with the local nervous circuitry.
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So, P. T. C., C. Y. Dong, C. Buhler, and E. Gratton. "Time-Resolved Stimulated-Emission Fluorescence Microscope." Proceedings, annual meeting, Electron Microscopy Society of America 54 (August 11, 1996): 278–79. http://dx.doi.org/10.1017/s042482010016385x.

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Time-resolved stimulated-emission fluorescence microscopy is a novel technique for obtaining super-diffraction limited spatial resolution and sub-nanosecond time resolution using a multi-photon process. This technique is inspired by traditional asynchronous stimulated-emission pump-probe spectroscopy. Fluorescence sample is first excited by a pump laser pulse, tuned to the molecular absorption band of the molecule. Within the chromophore lifetime, a second probe pulse, tuned to the emission band, stimulates fluorescence emission.The spatial resolution enhancement originates from the bilinear dependence of the stimulated emission efficiency on both the pump and probe beam intensities. At the objective focal point, the stimulated emission point spread function is the product of the point spread functions of the pump and probe beams. This situation is mathematically equivalent to both the confocal and the two-photon methods. 3-D depth discrimination and superior spatial resolution is expected.
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Chen, Dihan, Mindan Ren, Dapeng Zhang, Jialong Chen, Songyun Gu, and Shih-Chi Chen. "Design of a multi-modality DMD-based two-photon microscope system." Optics Express 28, no. 20 (September 24, 2020): 30187. http://dx.doi.org/10.1364/oe.404652.

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Chuah, J., and D. Holburn. "Scalable and Configurable Multi-pixel CMOS Photon Detector for the Scanning Electron Microscope." Microscopy and Microanalysis 18, S2 (July 2012): 1222–23. http://dx.doi.org/10.1017/s1431927612007969.

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Pegoraro, A., A. Ridsdale, RK Lyn, JP Pezacki, and A. Stolow. "Simple High Performance Multi-modal Coherent Anti-Stokes Raman Scattering (CARS) Microscopy Based on a Two-Photon Microscope." Microscopy and Microanalysis 14, S2 (August 2008): 758–59. http://dx.doi.org/10.1017/s1431927608086911.

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George, Nicholas M., Arianna G. Polese, Greg Futia, Baris Ozbay, Wendy Macklin, Emily Gibson, Aviva Abosch, Diego Restrepo, and Brian E. Moore. "2507 A novel multi-photon microscopy method for neuronavigation in deep brain stimulation surgery." Journal of Clinical and Translational Science 2, S1 (June 2018): 2–3. http://dx.doi.org/10.1017/cts.2018.40.

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OBJECTIVES/SPECIFIC AIMS: The goal for this project is to determine the feasibility of using a novel multi-photon fiber-coupled microscope to aid surgeons in localizing STN during surgeries. In order to accomplish this goal, we needed to identify the source of a strong autofluorescent signal in the STN and determine whether we could use image classification methods to automatically distinguish STN from surrounding brain regions. METHODS/STUDY POPULATION: We acquired 3 cadaveric brains from the University of Colorado Anschutz Medical Campus, Department of Pathology. Two of these brains were non-PD controls whereas 1 was diagnosed with PD. We dissected a 10 square centimeter region of midbrain surrounding STN, then prepared this tissue for slicing on a vibratome or cryostat. Samples were immuno-labeled for various cellular markers for identification, or left unlabeled in order to observe the autofluorescence for image classification. RESULTS/ANTICIPATED RESULTS: The border of STN is clearly visible based on the density of a strong autofluorescent signal. The autofluorescent signal is visible using 2-photon (850–1040 nm excitation) and conventional confocal microscopy (488–647 nm excitation). We were also able to visualize blood vessels with second harmonic generation. The autofluorescent signal is quenched by high concentrations of Sudan-black B (0.5%–5%), and is primarily localized in microtubule-associated protein-2 (MAP2)+ cells, indicating that it is likely lipofuscin accumulation in neurons. Smaller lipofuscin particles also accumulate in microglia, identified based on ionized calcium binding adopter 1 (Iba1)+ labeling. We anticipate that colocalization analysis will confirm these qualitative observations. Using 2-photon images of the endogenous autofluorescent signal in these samples, we trained a logistic regression-based image classifier using features derived from gray-level co-occurrence matrices. Preliminary testing indicates that our classifier performed well, with a mean accuracy of 0.89 (standard deviation of 0.11) and a Cohen’s Kappa value of 0.76 (standard deviation of 0.24). We are currently using coherent anti-Stokes Raman scattering and third harmonic imaging to identify different features of myelin that can be used to distinguish between these regions and expect similar results. DISCUSSION/SIGNIFICANCE OF IMPACT: Traditional methods for localizing STN during DBS surgery include the use of stereotactic coordinates and multi-electrode recording (MER) during implantation. MERs are incredibly useful in DBS surgeries, but require penetration of brain structures in order to infer location. Using multi-photon microscopy techniques to aid identification of STN during DBS surgeries offers a number of advantages over traditional methods. For example, blood vessels can be clearly identified with second harmonic generation, something that is not possible with MER. Multi-photon microscopy also allows visualization deep into tissue without actually penetrating it. This ability to look within a depth of field is useful for detection of STN borders based on autofluorescent cell density. When combined with traditional stereotactic information, our preliminary image classification methods are a fast, reliable way to provide surgeons with extra information concerning their location in the midbrain. We anticipate that future advancements and refinements to our image classifier will only increase accuracy and the potential applications and value. In summary, these preliminary data support the feasibility of multi-photon microscopy to aid in the identification of target brain regions during DBS surgeries. The techniques described here complement and enhance current stereotactic and electrophysiological methods for DBS surgeries.
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Vlieg, Redmar C., and John van Noort. "Multiplexed two-photon excitation spectroscopy of single gold nanorods." Journal of Chemical Physics 156, no. 9 (March 7, 2022): 094201. http://dx.doi.org/10.1063/5.0073208.

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Plasmonic metallic nanoparticles are commonly used in (bio-)sensing applications because their localized surface plasmon resonance is highly sensitive to changes in the environment. Although optical detection of scattered light from single particles provides a straightforward means of detection, the two-photon luminescence (TPL) of single gold nanorods (GNRs) has the potential to increase the sensitivity due to the large anti-Stokes shift and the non-linear excitation mechanism. However, two-photon microscopy and spectroscopy are restricted in bandwidth and have been limited by the thermal stability of GNRs. Here, we used a scanning multi-focal microscope to simultaneously measure the two-photon excitation spectra of hundreds of individual GNRs with sub-nanometer accuracy. By keeping the excitation power under the melting threshold, we show that GNRs were stable in intensity and spectrum for more than 30 min, demonstrating the absence of thermal reshaping. Spectra featured a signal-to-noise ratio of >10 and a plasmon peak width of typically 30 nm. Changes in the refractive index of the medium of less than 0.04, corresponding to a change in surface plasmon resonance of 8 nm, could be readily measured and over longer periods. We used this enhanced spectral sensitivity to measure the presence of neutravidin, exploring the potential of TPL spectroscopy of single GNRs for enhanced plasmonic sensing.
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Dissertations / Theses on the topic "Multi-Photon microscope"

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Chuah, Joon Huang. "A multi-pixel CMOS photon detector for the scanning electron microscope." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608077.

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Guillemant, Marie. "Development of a three-photon microscope for awake and behaving non-human primates." Electronic Thesis or Diss., université Paris-Saclay, 2023. http://www.theses.fr/2023UPASL025.

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La microscopie multiphotonique est devenue un outil essentiel pour étudier l'activité fonctionnelle de la souris mais son application à des animaux plus grands se heurte à plusieurs obstacles. Il serait particulièrement avantageux de pouvoir l'appliquer aux macaques, car ils représentent un modèle animal de choix pour comprendre les mécanismes neuronaux des fonctions cognitives de haut niveau, telles que l'attention, la mémoire et la conscience. L'un des principaux facteurs limitant à l'imagerie chez les grands animaux est la dure-mère. Cette couche de tissu épaisse et opaque protège le cerveau, mais elle est si épaisse chez les grands animaux qu'elle entrave l'imagerie. Elle est donc couramment enlevée mais cela conduit à une préparation hautement invasive et instable. L'objectif principal de ce travail est d'étudier la possibilité d'enregistrer l'activité fonctionnelle du cortex du macaque rhésus à travers la dure-mère naturelle.Une installation de microscopie multiphotonique a été conçue avec des chemins optiques de microscopie à deux et trois photons pour pouvoir faire des enregistrements sur des primates non humains vigiles. La fréquence de répétition du laser est de 2MHz, ce qui permet une profondeur d'imagerie maximale à l'intérieur du cortex de 520µm à 960nm et 715µm à 1300nm en la présence d'une dure-mère de 120µm d'épaisseur à la surface. Le champ de vision est de 620x630µm² avec une fréquence d'acquisition de 7,8Hz en utilisant un balayage unidirectionnel. En plus de cette installation, des implants chirurgicaux ont été développés pour une imagerie stable sur le long-terme de sujets vigiles.En utilisant une étude ex vivo de la dure-mère d'un macaque rhésus, les aberrations optiques induites par celle-ci ont été étudiées en mesurant la diminution de la résolution spatiale du microscope pour une épaisseur variable de dure-mère. Ceci révèle qu'elle n'a pas d'impact significatif sur la résolution pour une épaisseur allant jusqu'à 150µm à 1300nm. La longueur d'atténuation effective de la dure-mère naturelle est estimée à 56.5±10.1µm à 960nm et 80.7±5.3µm à 1300nm. Ces valeurs sont utilisées pour modéliser la profondeur maximale d'imagerie en fonction de la fréquence de répétition du laser et de l'épaisseur de la dure-mère.Ce modèle est ajusté et validé à l'aide de données in vivo provenant de deux primates non humains. La longueur d'atténuation effective de la dure-mère naturelle et d'une repousse de tissu après une durectomie (appelée "néomembrane") sont étudiées. Des enregistrements fonctionnels ont été réalisés chez la souris et prétraités avec Suite2P. Les paramètres d'injection virale ont été testés chez trois macaques et nous avons enregistré l'activité structurelle et fonctionnelle de neurones pour l'un d'eux au moment de l'étude.Enfin, la comparaison entre l'utilisation de la microscopie à deux ou trois photons pour l'étude du primate non humain est discutée.En conclusion, nous avons mis en place et optimisé un microscope multiphotonique pour l'imagerie vigile et à long-terme du cortex de primates non-humains et montré qu'il était possible d'enregistrer le cortex jusqu'à plus de 700µm de profondeur (ce qui correspond aux couches L2/L3) tout en gardant la dure-mère naturelle en place
Multi-photon microscopy has become a standard technique to study the structural and functional activity in mice but it faces obstacles to be applied in larger animals. It would be particularly advantageous to be able to apply it to macaque monkeys, as they are the animal model of choice to understand the neural mechanisms of high-level cognitive functions such as selective attention, working memory and consciousness. One of the main limiting factors for imaging in larger animals is the dura mater. This tough and opaque layer of tissue protects the brain but is so thick in larger animals that it obstructs imaging. It is therefore commonly removed but this leads to a highly invasive and unstable preparation. The main aim of the current work is to investigate the possibility to record functional activity from the cortex of the rhesus macaque monkey through the natural dura.A multi-photon microscopy setup has been designed with a two-photon and a three-photon microscopy optical paths to record from awake macaque monkeys. The repetition rate of the laser is 2MHz which allows a maximum imaging depth inside the cortex of 520µm at 960nm and 715µm at 1300nm with an additional 120µm-thick layer of dura mater at the surface. Resonance-galvo scanning is used to allow a maximal frame rate of 15.6Hz at a field of view of 620x630µm². In addition to the setup, surgical implants have been developed for long-term and awake imaging.Using an ex vivo study of dura mater from a macaque monkey, the induced optical aberrations are studied by measuring the decrease in spatial resolution of the setup for a varying thickness of dura mater. This reveals that it has no significant impact on the spatial resolution for a thickness up to 150µm at 1300nm. The effective attenuation length of the dura mater is estimated to be 56.5±10.1µm at 960nm and 80.7±5.3µm at 1300nm. These measurements are used to model the maximum imaging depth that can be reached according to the repetition rate of the laser and the thickness of the dura.This model is adjusted and validated using in vivo data from two non-human primates. The effective attenuation length of the natural dura mater and of a regrowth of tissue following a durectomy (called a 'neomembrane') are investigated. Functional recordings have been performed in mice and preprocessed using Suite2P. Viral injection parameters have been tested in three macaque monkeys and we have so far recorded the in vivo structural and functional activity of neurons in one. Finally, the comparison between the use of two- and three-photon microscopy to study non-human primates is discussed. In conclusion, we have set up and optimized a multi-photon microscope for long-term awake imaging of the cortex of non-human primates and shown that it was possible to record down to over 700µm into the cortex (which corresponds to the layers L2/L3) while imaging through the natural dura mater or a neomembrane
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Mansfield, Jessica. "Multi-photon microscopy of cartilage." Thesis, University of Exeter, 2008. http://hdl.handle.net/10036/42345.

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Articular cartilage has been imaged using the following multi-photon modalities: Second Harmonic Generation (SHG), Two-photon Fluorescence (TPF) and Coherent Anti-Stokes Raman Scattering (CARS). A simple epi detection microscope was constructed for SHG and TPF imaging in the early stages of this research. Later the imaging was transferred to a new microscope system which allowed simultaneous forwards and epi detection and combined CARS imaging with TPF and SHG. Multiphoton spectroscopic studies were conducted on both intact tissue samples and the major components of the extracellular matrix, in order to identify sources of TPF. Fluorescence was detected from type II collagen, elastin and samples of purified collagen and elastin crosslinks. Age related glycation crosslinks of collagen may be a significant source of TPF. No fluorescence was detected from proteoglycans. In intact, unfixed healthy articular cartilage the cells were observed via CARS, surrounded in their pericellular matrix which is characterised by an increase in TPF. The collagen of the extra cellular matrix showed up clearly in the SHG images. Diseased cartilage was also imaged revealing microscopic lesion at the articular surface in early osteoarthritis and highly fibrous collagen structures and cell clusters in more advanced degeneration. In young healthy cartilage a network of elastin fibres were found lying parallel to the articular surface in the most superficial 50μm of the tissue. Regional variations in these fibres were also investigated. The fibres appeared mainly long and straight suggesting that they may be under tension, further work is needed to identify whether they have a mechanical function. The polarization sensitivity of the SHG from collagen has been investigated for both cartilage and tendon. In the most superficial tissue these measurements can be used directly to determine the collagen fibre orientation. However at increasing depths the effects of biattenuation and birefringence must be considered. Healthy cartilage has a characteristic pattern of polarization sensitivity with depth and this changes at lesions indicating a disruption of the normal collagen architecture. The methods developed in this thesis demonstrate the use of non-linear microscopy to visualise the structure of the extracellular matrix and cells in intact unstained tissue. They should also be appropriate in many areas of cell and matrix biology.
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Tsikritsis, Dimitrios. "Vibrational spectroscopy and microscopy in colorectal cancer." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33049.

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This project set out to examine the possibility that by acquiring Raman spectra and performing multi-photon imaging we can get better diagnosis and understanding of the biochemistry of an individual cancerous tumour and distinguish it from the healthy tissue. Within the frame of this study, colorectal primary and secondary cancer cells are examined with Raman spectroscopy in order to (i) study and distinguish them according to their chemical composition by applying multivariate methods and (ii) determine whether Raman spectroscopy can identify the cells which are the link between primary and secondary colorectal cancer cells, the so-called Cancer Stem Cells. The second part of this thesis is based on tissue studies. Human colorectal tissue sections are examined in a label-free manner with the use of multi-photon imaging modes (i) Two photon excitation fluorescence, (ii) stimulated Raman scattering and (iii) second harmonic generation, in order to determine whether these can provide fast and accurate diagnosis of colorectal cancer. These techniques were able to distinguish between healthy and cancerous tissue regions, based on the chemically-specific images of the tissue microenvironment and architecture. The hypothesis of Cancer stem cell is examined with the use of Raman spectroscopy shown that the CSCs have some small differences according to their tissue origin.
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Romijn, Elisabeth Inge. "Development of 3-D Quantitative Analysis of Multi-Photon Microscopy Images." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for fysikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18425.

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Motivation: Cartilage is a robust but flexible connective tissue found in most joints of the body. The collagen fibres present in the extracellular matrix of cartilage contribute to its tensile strength and stiffness. The purpose of this study is to develop and implement methods to determine the orientation and anisotropy of collagen fibres in 3-D images gen- erated with multi-photon microscopy. The motivation behind developing these techniques is to improve the foundation for further studies on understanding the characteristics of the cartilage matrix. This in turn would give a better foundation for developing artificial matrices and mechanical models, as well as improve diagnostics.Material and methods: The two methods developed in this study are based on analysing the frequency domain. One is an expansion of a previous developed method by Chaudhuri et al. [1]. This method is based on evaluating the average intensity at different directions in the frequency domain. The direction with the least average intensity is equivalent to the direction of the fibres. The other method is based on thresholding the frequency domain according to intensity followed by fitting an ellipsoid to the remaining data set. The direction of the collagen fibres is equivalent to the direction of the shortest axis of the ellipsoid. These methods are called the sector and ellipsoid method, respectively. To determine how robust these methods are a series of tests were developed. The focus of these tests was to determine if the methods are rotational invariant and if the results are influences by different preprocessing techniques. These preprocessing techniques are: median filtering, deconvolution and skeletonization of the original image containing the collagen fibres. It is also important to determine the sensitivity of the ellipsoid method according to the chosen threshold value. In addition data generated fibres and frequency domains were made to determine the accuracy of the methods.Results and conclusion: The sector method was not very robust. For most cases there is not one specific direction that has the least average intensity in the frequency domain. Instead there is a quite large minimum area. The ellipsoid method shows promising results. It managed to find the correct direction both for the data generated data sets, but also for the real images. It seems like no preprocessing nor frequency filtering, except for thresholding, is needed to still find the correct direction and its anisotropy. The only remark is that the automatically chosen threshold value was to low for one of the samples. This can probably be improved by making a slight change in the process for choosing a threshold value.
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Chalal, Mohand. "Structure multi-échelle et propriétés physico-chimiques des gels de polymères thermosensibles." Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00680076.

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La "cryopolymérisation" permet d'obtenir des gels de polymère macroporeux ou "cryogels". Cette méthode a été utilisée pour la synthèse d'hydrogels thermosensibles à base de pNIPA. La température critique TC correspondant à la transition de volume a été déterminée par des mesures de taux de gonflement et par DSC. La macroporosité (distribution de la taille des pores et épaisseur des parois) et son évolution en fonction de T ont été étudiées par la microscopie biphotonique donnant des informations à l'échelle du µm à plusieurs dizaines de µm. La diffusion de rayons X (SAXS et WAXS) a été utilisée pour caractériser la structure multi-échelle (de quelques dixièmes à quelques dizaines de nm) du gel constituant les parois des macropores. Les courbes de diffusion ont été décrites analytiquement. L'évolution des dix paramètres contenus dans l'équation a été étudiée en fonction de T et discutée. Enfin, des expériences utilisant les phonons hyperfréquences générés par la technique des réseaux transitoires avec détection hétérodyne (HD-TG) ont été réalisées. Ces mesures ont permis de déterminer la vitesse de propagation de l'onde ultra-sonore (à 340 MHz), son atténuation, et la constante de diffusion thermique à différentes températures.
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Gasecka, Alicja. "Microscopie non-lineaire polarimetrique dans les milieux moleculaires et biologiques." Phd thesis, Université Paul Cézanne - Aix-Marseille III, 2010. http://tel.archives-ouvertes.fr/tel-00560415.

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Les interactions lumière-matière dans les mileux moléculaires et bio-moléculaires peuvent mener à des processus complexes où les polarisations des champs optiques se couplent aux assemblages de dipoles de transitions moléculaires. La manipulation des polarisations des champs optiques en microscopie de uorescence peut en particulier donner accès à des modi cations nes d'arrangements moléculaires. Dans ce travail de thèse nous introduisons une méthode basée sur la variation continue d'un état de polarisation d'excitation complémentée par une analyse polarisée, appliquée à la microscopie de uorescence multi-photons. La uorescence à deux photons polarimétrique permet d'accéder à une information statique quantitative sur la forme et l'orientation de la distribution orientationnelle moléculaire dans des membranes lipidiques articielles, dans des cellules ou sur des composés molécluaires co-cristallins qui peuvent être fortement hétérogènes. La uorescence à trois photons polarimétrique apporte de plus un diagnostique de cristallinité dans des cristaux de protéines, avec une forte sensibilité à leur structure et symétrie. L'implémentation expérimentale de cette technique requiert de quantier les distortions de polarisation provenant du montage expérimental et de l'échantillon lui-même, qui sont nement analysés.
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Guiet, Romain. "Étude des mécanismes cellulaires et moléculaires de la migration des macrophages humains dans des environnements en trois dimensions." Toulouse 3, 2011. http://thesesups.ups-tlse.fr/1487/.

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L'infiltration tissulaire des macrophages est un facteur aggravant dans de nombreuses pathologies telles que les maladies inflammatoires chroniques ou le cancer. Les macrophages qui infiltrent les tumeurs de façon continue sont appelés macrophages associés aux tumeurs (TAMs). Ils favorisent la croissance tumorale, l'angiogenèse, l'invasion tumorale et la formation de métastases. L'inhibition de l'infiltration des macrophages est donc devenue une évidence thérapeutique. Récemment, l'équipe a démontré que les macrophages utilisent le mode migratoire amiboïde (dépendant de ROCK) ou mésenchymal (dépendant des protéases) selon l'architecture de la matrice extracellulaire (MEC) en trois-dimensions (3D) qu'ils traversent. De plus, l'étude du mode migratoire mésenchymal a montré qu'il est dépendant de Hck (une tyrosine kinase spécifique des phagocytes) et de sa capacité à réorganiser les podosomes en rosettes (structures riches en actine dégradant la MEC). Mon projet de thèse s'est articulé autour de deux axes de recherche : 1) l'identification des substrats de Hck et la caractérisation de leur rôle dans l'organisation des podosomes et la migration 3D des macrophages, et 2) l'étude de la migration 3D des monocytes/macrophages primaires humains dans un modèle mimant le microenvironnement tumoral : les sphéroïdes tumoraux. Par une approche protéomique j'ai identifié des partenaires et substrats potentiels de Hck dont la Filamine A (FLNa), une protéine assurant notamment la liaison entre le cytosquelette d'actine et les intégrines. En utilisant différents outils (protéines recombinantes, anticorps, shRNA. . . ) j'ai montré que : 1) Hck phosphoryle la FLNa in vitro, 2) la FLNa est associée aux podosomes et est nécessaire à leur organisation en rosettes sous le contrôle de Hck, 3) les podosomes des cellules déficientes en Flna ont une durée de vie plus courte, et 4) l'expression de la FLNa est nécessaire à la migration mésenchymale, mais pas à la migration amiboïde des macrophages dans une MEC en 3D. Ainsi la FLNa est impliquée dans la formation et à la stabilisation des podosomes, à leur organisation en rosettes, la migration mésenchymale des macrophages et pourrait se situer dans la voie de signalisation de Hck. En parallèle, j'ai mis au point un modèle de sphéroïdes tumoraux qui m'a permis de montrer que l'infiltration des monocytes ou des macrophages, dans ce modèle tissulaire in vitro, est dépendante de ROCK et des protéases, signature de l'utilisation des deux modes migratoires. Puis en incubant ces sphéroïdes au sein de MEC, j'ai démontré que la présence de macrophages infiltrés dans les sphéroïdes est nécessaire pour déclencher le pouvoir invasif des cellules tumorales qui émigrent des sphéroïdes en suivant les macrophages et infiltrent la MEC environnante. Les macrophages Hck-/- présentant un défaut de migration mésenchymale, sont significativement moins efficaces dans la promotion de l'invasion des cellules tumorales. Ces résultats indiquent que l'activité de migration et de remodelage de la matrice exercée par les macrophages est prépondérante dans l'invasion tumorale in vitro. Ces résultats ont permis d'établir le mode migratoire des macrophages infiltrant un modèle tissulaire in-vitro et de démontrer le mécanisme d'action des macrophages dans l'invasion tumorale. Ainsi, mes travaux de thèse ont permis de progresser dans la caractérisation des mécanismes moléculaires et cellulaires de la migration 3D des macrophages humains. En effet, j'ai pu 1) identifier une protéine nécessaire à la migration mésenchymale des macrophages, 2) mettre en évidence l'utilisation par les macrophages des modes migratoires amiboïde et mésenchymal lors de leur infiltration dans un modèle de tumeur en trois-dimensions, les sphéroïdes tumoraux et 3) montrer que le remodelage de la matrice par les macrophages, lors de leur migration, joue un rôle prépondérant dans l'invasion tumorale
Tissue infiltration of macrophages is an aggravating factor in many diseases such as chronic inflammation and cancer. Macrophages that infiltrate tumors are called tumor-associated macrophages (TAMs). They promote tumor growth, angiogenesis, invasion and metastasis. Thus, inhibition of macrophage infiltration has become a therapeutic goal. Recently, the team demonstrated that macrophages use the amoeboid (depending on ROCK) or the mesenchymal (depending on proteases) migratory mode according to the extracellular matrix (ECM) architecture in three dimensions (3D). In addition, the study of the mesenchymal migration mode showed that it is dependent on Hck (a phagocyte-specific tyrosine kinase) and its ability to reorganize podosomes (ECM-degrading actin-rich structures) into rosettes. My thesis project was organized around two axes 1) the identification of substrates of Hck and the characterization of their role in the organization of podosomes and 3D migration of macrophages, and 2) the study of the 3D migration mechanisms of primary human monocytes/ macrophages within an in vitro tumor model: tumor cell spheroids. By a proteomic approach, I have identified potential partners and substrates of Hck, including the protein Filamin A (FLNa), a protein interacting with the actin cytoskeleton and integrins. Using different tools (recombinant proteins, antibodies, shRNA. . . ) I showed that: 1) Hck phosphorylates FLNa in vitro, 2) FLNa is localized to podosomes and is necessary for their organization as rosettes under the control of Hck, 3) the podosomes of FLNa-deficient cells have a shorter life span, and 4) the expression of FLNa is required for mesenchymal migration, but not for amoeboid migration of macrophages in a 3D ECM. Thus, FLNa could be a substrate of Hck necessary for the formation and stabilization of podosomes and their organization as rosettes, and is required for the mesenchymal migration of macrophages. In parallel, I developed a model of tumor cell spheroids, which allowed me to show that the infiltration of monocytes or macrophages in this in vitro tissue model of tumor is dependent on ROCK and proteases, signature of the use of the two migration modes. Then, when spheroids were embedded into ECM, I demonstrated that the presence of macrophages infiltrated into the spheroids is necessary to trigger the invasiveness of tumor cells. Indeed, macrophages infiltrate first the surrounding ECM and tumor cells follow macrophages in the matrix outside of the spheroid. Hck-/- macrophages, that are defective in mesenchymal migration, are significantly less effective in promoting the invasion of tumor cells. These results indicate that the activity of migration and matrix remodeling exerted by macrophages is prominent in tumor invasion. These results have established the migratory mode of macrophages infiltrating an in vitro tumor model and a mechanism required for tumor invasiveness promoted by macrophages. Thus during my thesis, I characterized the molecular and cellular mechanisms of 3D migration of human macrophages. Indeed, I have been able to: 1) identify a protein necessary for the mesenchymal migration of macrophages, 2) highlight the use by macrophages of the amoeboid and mesenchymal migration modes during their infiltration into an in vitro tumor model in 3D and 3) show that the matrix remodeling activity of macrophages during their migration plays a critical role in tumor cell invasion
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Leclerc, Pierre. "Développement d’un endomicroscope multiphotonique à deux couleurs pour l’imagerie du métabolisme énergétique cellulaire." Thesis, Limoges, 2017. http://www.theses.fr/2017LIMO0053/document.

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La microscopie multiphotonique est une modalité d’imagerie de pointe offrant des opportunités d’avancées remarquables en biologie mais aussi dans le domaine médical. Afin d’en exploiter pleinement le formidable potentiel au cœur même de la pratique clinique, le développement de nombreuses sondes miniaturisées à fibre optique pour l’endomicroscopie multiphotonique (EMMP) a eu lieu depuis de nombreuses années et dans de nombreux laboratoires français et étrangers. Il s’est pour l'instant confronté à des limitations majeures comme l’impossibilité de recueillir les signaux d’auto-fluorescence des tissus qui sont intrinsèquement faibles comme ceux venant des co-enzymes métaboliques NADH et FAD. Cette limitation compromet l'utilité de l’EMMP en la restreignant à une imagerie morphologique requérant un marquage exogène des tissus. Ce manuscrit présente une architecture d’EMMP permettant de dépasser cette limitation, capable de proposer une imagerie fonctionnelle du métabolisme cellulaire en temps réel, in vivo, in situ, sans marquage. Le prototype d’EMMP proposé est une amélioration du précédent, où les Grisms en réflexions sont remplacés par des Grisms en transmission, permettant d’élargir la bande spectrale d’utilisation et la transmission du système. Ce prototype voit aussi l’adjonction d’un second laser excitateur afin d’accéder aux fluorescences du NADH et du FAD. Les résultats démontrent capable que nous sommes à même d’imager les fluorescences cellulaires intrinsèques au travers de 5 mètres de fibre optique avec une résolution subcellulaire. Parmi celles-ci nous sommes capables d’exciter et de collecter spécifiquement les fluorescences du NADH et du FAD. Enfin nous détectons assez de photons pour disposer d‘informations quantitatives et donc de proposer une image du rapport d’oxydo-réduction optique en endomicroscopie
Nonlinear microscopy is a cutting edge imaging modality leading to remarkable step forward in biology but also in the clinical field. To use it at its full potential and at the very heart of clinical practice, there has been several development of fiber-based micro-endoscope. The application for those probes is now limited by few major restrictions, such as the impossibility to collect auto-fluorescence signal from tissues theses being inherently weak such as the fluorescence from NADH or FAD. This limitation reduces the usefulness of the micro-endoscope effectively restraining it to morphological imaging modality requiring staining of the tissue. Our aim is to go beyond this limitation, showing cellular metabolism monitoring, in real time, without any staining. The experimental setup is an upgrade of our precedent one where the reflection- based Grism stretcher is replace with a new generation transmission-based Grism stretcher. Another Laser was also added in order to tune the first laser at 860nm to allow FAD imaging and the second one to 760nm for NADH. The results prove that we assess and image the level of NADH and FAD at subcellular resolution through a five-meter-long fiber. Thus we demonstrate that we are capable of measuring the optical redox ratio in a micro-endoscopic configuration
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Liu, Li. "Roles of PMCA Isoforms in Ca2+-Homeostasis and Contractility of Bladder Smooth Muscle: Evidence from PMCA Gene-Ablated Mice." Cincinnati, Ohio : University of Cincinnati, 2007. http://rave.ohiolink.edu/etdc/view.cgi?acc_num=ucin1178307168.

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Thesis (Ph.D.)--University of Cincinnati, 2007.
Advisor: Richard J. Paul. Title from electronic thesis title page (viewed Apr. 4, 2009). Keywords: PMCA (human gene symbols; ATP2B); SERCA2 (human gene symbols; ATP2A2); NCX; bladder smooth muscle; Ca²⁺ homeostasis; gene-altered mice. Ca²⁺ waves; Ca²⁺ sparks; Fura-PE3; Fluo-4; Indo-1; multi-photon microscopy. Includes abstract. Includes bibliographical references.
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Books on the topic "Multi-Photon microscope"

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Dickson, Andrew. Multi-Photon Laser Scanning Microscopy. Bios Scientific Pub Ltd, 2002.

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Dixon, John. Multi-Photon Laser Scanning Microscopy. Taylor & Francis Group, 2004.

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Dickson, Andrew. Multi Photon Laser Scanning Microscopy. Springer-Verlag Telos, 2002.

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Petrov, V. V., A. A. Kryuchyn, Ie V. Beliak, and A. S. Lapchuk. Multi-Photon Microscopy and Optical Recording. PH "Akademperiodyka", 2016. http://dx.doi.org/10.15407/akademperiodyka.311.156.

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Book chapters on the topic "Multi-Photon microscope"

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Bewersdorf, Jörg, Alexander Egner, and Stefan W. Hell. "Multifocal Multi-Photon Microscopy." In Handbook Of Biological Confocal Microscopy, 550–60. Boston, MA: Springer US, 2006. http://dx.doi.org/10.1007/978-0-387-45524-2_29.

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So, Peter T. C. "Multi-photon Excitation Fluorescence Microscopy." In Frontiers in Biomedical Engineering, 529–44. Boston, MA: Springer US, 2003. http://dx.doi.org/10.1007/978-1-4419-8967-3_35.

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Murti, Y. V. G. S., and C. Vijayan. "Basics of Multi-photon Microscopy." In Physics of Nonlinear Optics, 157–68. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-73979-9_9.

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König, Karsten. "Cell Damage During Multi-Photon Microscopy." In Handbook Of Biological Confocal Microscopy, 680–89. Boston, MA: Springer US, 2006. http://dx.doi.org/10.1007/978-0-387-45524-2_38.

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Sandoval, Ruben M., and Bruce A. Molitoris. "Fluorescent Dextrans in Intravital Multi-Photon Microscopy." In Advances in Intravital Microscopy, 205–19. Dordrecht: Springer Netherlands, 2014. http://dx.doi.org/10.1007/978-94-017-9361-2_10.

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Denk, Winfried, David W. Piston, and Watt W. Webb. "Multi-Photon Molecular Excitation in Laser-Scanning Microscopy." In Handbook Of Biological Confocal Microscopy, 535–49. Boston, MA: Springer US, 2006. http://dx.doi.org/10.1007/978-0-387-45524-2_28.

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Hardin, Jeff. "Confocal and Multi-Photon Imaging of Living Embryos." In Handbook Of Biological Confocal Microscopy, 746–68. Boston, MA: Springer US, 2006. http://dx.doi.org/10.1007/978-0-387-45524-2_43.

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Molitoris, Bruce A., and Ruben M. Sandoval. "Quantifying Dynamic Kidney Processes Utilizing Multi-Photon Microscopy." In Contributions to Nephrology, 227–35. Basel: KARGER, 2007. http://dx.doi.org/10.1159/000102088.

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Ghafaryasl, Babak, Bart H. Bijnens, Erwin van Vliet, Fátima Crispi, and Rubén Cárdenes. "Cardiac Microstructure Estimation from Multi-photon Confocal Microscopy Images." In Functional Imaging and Modeling of the Heart, 80–88. Berlin, Heidelberg: Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-38899-6_10.

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Egner, Alexander, and Stefan W. Hell. "Aberrations in Confocal and Multi-Photon Fluorescence Microscopy Induced by Refractive Index Mismatch." In Handbook Of Biological Confocal Microscopy, 404–13. Boston, MA: Springer US, 2006. http://dx.doi.org/10.1007/978-0-387-45524-2_20.

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Conference papers on the topic "Multi-Photon microscope"

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Marti, Dominik, Martin Djurhuus, Ole Bjarlin Jensen, and Peter E. Andersen. "Multi-photon microscope driven by novel green laser pump." In SPIE BiOS, edited by Ammasi Periasamy, Peter T. C. So, and Karsten König. SPIE, 2016. http://dx.doi.org/10.1117/12.2208586.

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Gonçalves, Odete, Scott Snider, Ruben Zadoyan, Quoc-Thang Nguyen, Henrik Vorum, Steffen B. Petersen, and Maria Teresa Neves-Petersen. "Novel microfabrication stage allowing for one-photon and multi-photon light assisted molecular immobilization and for multi-photon microscope." In SPIE BiOS, edited by Samuel Achilefu and Ramesh Raghavachari. SPIE, 2017. http://dx.doi.org/10.1117/12.2250567.

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Schenkl, Selma, Eike Weiss, Martin Stark, Frank Stracke, Iris Riemann, Robert Lemor, and Karsten König. "Imaging living cells with a combined high-resolution multi-photon-acoustic microscope." In Biomedical Optics (BiOS) 2007, edited by Alexander A. Oraevsky and Lihong V. Wang. SPIE, 2007. http://dx.doi.org/10.1117/12.702391.

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Milster, Tom D., Youngsik Kim, and Phat Lu. "Hyper-NA (NA = 2.8) Microscope Using 1.55um fs Source for Multi-Photon Imaging." In Bio-Optics: Design and Application. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/boda.2013.bt1a.2.

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Tjokro, Cahyadi, and Colin J. R. Sheppard. "Phase space analysis of photon scattering in multi planes within a microscope system." In SPIE Proceedings, edited by Valery V. Tuchin. SPIE, 2006. http://dx.doi.org/10.1117/12.697072.

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Matsumoto, Naoya, Shigetoshi Okazaki, Hisayoshi Takamoto, Takashi Inoue, and Susumu Terakawa. "Modulation of the pupil function of microscope objective lens for multifocal multi-photon microscopy using a spatial light modulator." In SPIE BiOS, edited by Ammasi Periasamy, Peter T. C. So, and Karsten König. SPIE, 2014. http://dx.doi.org/10.1117/12.2038929.

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Squier, Jeffrey A. "A Pragmatic Guide to Building a Multi-Photon Microscope with Applications to Micro-Machining." In CLEO: Applications and Technology. Washington, D.C.: OSA, 2013. http://dx.doi.org/10.1364/cleo_at.2013.ctu3o.4.

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Yavaş, S., M. Erdoğan, K. Gürel, U. H. Tazebay, and F. Ö. Ilday. "Multi-photon ablation of biological samples with custom-built femtosecond fiber laser-microscope system." In Conference on Lasers and Electro-Optics. Washington, D.C.: OSA, 2010. http://dx.doi.org/10.1364/cleo.2010.jwa73.

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Karpf, Sebastian, and Bahram Jalali. "Spectrally-encoded Multi-photon Microscopy." In Novel Techniques in Microscopy. Washington, D.C.: OSA, 2017. http://dx.doi.org/10.1364/ntm.2017.nm4c.4.

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Hirao, K. "Writing Waveguides and Gratings in Silica and Related Materials by Femto-Second Laser." In Bragg Gratings, Photosensitivity, and Poling in Glass Fibers and Waveguides. Washington, D.C.: Optica Publishing Group, 1997. http://dx.doi.org/10.1364/bgppf.1997.btub.4.

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With the goal of being able to create various optical glass devices for the telecommunications industry, the effects of 810 nm, femto-second laser radiation on various glasses were investigated. By focusing the laser beam via a microscope objective, transparent but visible, round-elliptical damage lines were successfully written inside high silica, borate, soda-lime-silicate, fluoride and chalcogenide bulk glasses. Micro-ellipsometer measurements of the damaged region in pure and Ge-doped silica glasses showed a 0.01-0.035 refractive index increase, depending on the radiation dose. The formation of several types of defects including Si’E or Ge’E centers, non-bridging oxygen hole centers, and peroxy radicals was also detected. These results suggest that multi-photon interactions are occurring in the glasses and that it is possible to write three dimensional optical circuits in bulk glasses via such a focused laser beam technique. The following is the technique to create waveguides.
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