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1
Summerfield, Stephen. "Near infrared fluorescence spectroscopy." Thesis, Loughborough University, 1993. https://dspace.lboro.ac.uk/2134/10601.
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Fluorimetry in the very near infrared region ca. 600-1000nm is a new approach to photochemical analysis. The advantages include greatly reduced background fluorescence signals from important sample matrices (such as blood serum), reduced scattering, and reduced probability of sample decomposition. Also, the availability of low cost, efficient, stable and robust optical components (e.g. laser diodes and light emitting diodes), solid state detectors (e.g. single silicon photodiodes and diode arrays) and fibre optics, allows the construction of an inexpensive fluorimeter. In the near infrared region, there are some very bright fluorophores that can be adapted for use as fluorescent probes, labels for immunoassay, and as ion-pair agents. The advantageous performance of most types of fluorimetric analysis now undertaken In the ultraviolet and visible region of the spectrum may therefore be extended into the longer wavelength region. Excellent limits of detection are attainable, and some near infrared fluorophores show invaluable fluorescence probe properties, such as Nile Red. The most useful of the dye groups investigated were the phenoxazines and thiazines. Reactive derivatives of these dyes show great potential as fluorescent labels for Immunoassay. These dyes have also been used as probes due to their solvatochromism and sensitivity to pH.
2
Bello, K. A. "Near-infrared absorbing dyes." Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.375504.
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Wruck, Eric Michael. "Applying near-infrared spectroscopy (nirs)." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2386.
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Over recent decades, much has been learned about the perceptual capacity that
enables infants to recognize and understand language. However, not until very recently
have the neural mechanisms that are the substance of language learning been
investigated. A recently developed optical imaging technique called near-infrared
spectroscopy (NIRS) shows promise for being an acceptable alternative to invasive
imaging techniques. NIRS measures correlates of neural activity by assessing
hemoglobin concentration changes in the infant brain. The research presented here
investigates neural activation in the left temporal and occipital cortex regions during
exposure to speech and visual stimuli. As hypothesized, hemodynamic reaction was
observed in both areas. Results indicate a significant activation in response to speech in
the left temporal region, and an intriguing difference between uni- and bi-modally
presented speech stimuli. These results have interesting implications for future multimodal
studies of infant speech perception.
4
Andrew, Anne. "Standardisation of near infrared spectrophotometers." Thesis, University College London (University of London), 2005. http://discovery.ucl.ac.uk/1444341/.
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A near infrared (NIR) spectrometer produces, from a single sample, a spectrum formed from several hundred absorbance readings at a range of wavelengths in the NIR region. Using regression approaches and a large number of samples for which reference values and spectra are known, the instrument can be calibrated to predict reference values from spectra. A problem with NIR spectrometers is that no two instruments produce exactly the same output, as a result of which a calibration developed on one instrument cannot be transferred to a second instrument unless the second instrument has been standardised first. Our aim in this thesis is to explore and assess improved methods of standardising NIR spectrometers. The main line of attack is to use standard models but incorporate prior information through Bayesian techniques. The main commercially used standardisation techniques adjust the spectra wavelength by wavelength without any use being made of the fact that the spectra and therefore the appropriate adjustment varies smoothly. By the use of suitable priors within a Bayesian analysis we produce a better solution. The analysis is very time-consuming, involving inverting large matrices and MCMC or some other process for determining parameters. A second attempt using the same assumptions uses dynamic linear modelling, treating the spectra as time series. While theoretically slightly inferior, this method is very much quicker and produces comparable results. A third solution, while using the same basic model, makes an estimate of the wavelength shift in the wavelet domain. Our final, non-Bayes, method is intended to standardise a number of similar instruments simultaneously. This is achieved by projecting spectra onto a subspace orthogonal to the space spanned by between-instrument variation and calibrating on the subspace to produce a robust calibration.
5
Ennico, Kimberly Ann. "Near infrared faint object spectroscopy." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.625052.
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Angus, Caroline. "Near infrared spectroscopy and exercise." Thesis, University of Essex, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274298.
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Blount, Christopher. "Near infrared reflectance in Anura." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/near-infrared-reflectance-in-anura(f730de01-8d4a-43de-b2dd-2ef3027bfc2f).html.
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Increased near infrared (NIR) reflection, closely resembling the red edge found in leaves, has been known in frogs for many years. Whereas previously thought of as an isolated rarity, we have shown that it is likely far more prevalent than previously believed, occurring in multiple distinct family groups and world regions. To date, there are now 26 anuran species known to demonstrate increased NIR reflectance, from 12 different genera, 4 families, and 3 ecozones. The visible/NIR reflection spectra of each individual measured was found to be characteristic of its species; whether it was wild or captive bred; and its sex. A machine learning based classification system was demonstrated as a viable method of identifying these properties from a frog's reflection spectra alone. How this reflection spectra developed from a pre-metamorphosis froglet through to adult frog was tracked, with the gradual changes to the reflection spectra of both NIR reflective and other frogs identified as being most likely dominated by the reduction in epidermal melanophores, and the increasing number of dermal iridophores. A modified consumer camera was shown to be a viable method for rapid identification of increased NIR reflection in anurans, and was used to identify that salamanders also show variation in NIR reflection between ground dwelling and leaf sitting species. The overnight colour change in Hylomantis lemur was observed, and found to occur pre-emptively of the frog's future location; with the frogs regularly transitioning from pale green âÂÂdaytime' colouration, to the dark brown âÂÂnight time' colouration, while still on the green leaf surface before becoming active, and undertaking the reverse transition while still active, but shortly before returning to the leaf. It seems likely that this change is for protection from silhouetting whilst active. Optical coherence tomography images were taken of several species of frog, and found to be a viable method for non-invasive investigation of anuran skin structure, with structural differences observed between the two colourations of H. lemur. It was found that the most likely cause of the increased NIR reflection in frogs is a reduction in melanin, either by absence or substitution with pterorhodin. Although the true benefit to the frog is difficult to determine, it seems likely that cryptic thermoregulation plays a key role: the maintenance of body temperature for the purpose of camouflage from animals capable of far-infrared vision. This thesis demonstrates the legitimacy of several techniques and approaches for non-invasive study of anurans, but the ultimate scope of the project is fundamentally limited by the range of frogs available. Further insight is likely to arise from increasing this scope, applying these techniques to more frogs, from more species, in more regions, and the author wishes all future researchers the greatest success in this endeavour.
8
Prestwich, Andrea Heather. "Near infrared spectroscopy of galaxies." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47622.
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9
Smith, Leigh Charles. "Near-infrared proper motion surveys." Thesis, University of Hertfordshire, 2016. http://hdl.handle.net/2299/17192.
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I present the development of two near infrared proper motion pipelines for high resolution near infrared data from UKIDSS and the VISTA VVV survey. The UKIDSS pipeline is capable of accuracies of order 5-10 mas yr⁻¹ for bright sources with the largest epoch baselines (~ 8 years). The VVV pipeline reaches 1-2 mas yr⁻¹ proper motion precision at the bright end and parallax measurements at ~ 1 mas precision. It will be possible to improve upon the VVV astrometric precision due to increases in data volume and further pipeline development. I have used the proper motion pipelines to generate three near infrared proper motion catalogues of the UKIDSS LAS and GPS and the VVV survey. The LAS proper motion catalogue covers 1500 deg2 at high Galactic latitudes and contains approximately 15 million sources with two J band epochs. The GPS proper motion catalogue covers 1500 deg2 of the northern Galactic plane and contains approximately 400 million sources with two K band epochs. The VVV proper motion catalogue covers 560 deg2 of the Galactic bulge and disc and contains approximately 200 million sources with between 50 and 150 Ks band epochs. I have also produced a preliminary 5σ parallax catalogue containing 3403 VVV sources. The LAS and GPS proper motion catalogues have been used by myself and other authors to identify and study many new examples of high proper motion stars, brown dwarfs, ul-tracool dwarf benchmark candidates, cool white dwarfs, substellar subdwarfs and nearby sources within < 25 pc. These catalogues remain far from fully exploited and will be a useful resource for future research by the astronomical community. Exploitation of the VVV proper motion catalogue is still in its infancy, yet it has already generated large numbers of new high proper motion sources. These include new brown dwarf candi-dates, important benchmark objects, and nearby sources which have previously avoided detection. Parallax results from the VVV pipeline will be useful to improve low mass star/ultracool dwarf luminosity functions, significantly increasing the numbers of brown dwarfs with known parallaxes and illustrates how general purpose multi-epoch wide area surveys can generate parallaxes. Finally, I discuss the long term usefulness of such catalogues in the Gaia era and how they might be exploited in the future.
10
Corns, Stephen Nigel. "Novel near-infrared absorbing dyes." Thesis, University of Leeds, 1990. http://etheses.whiterose.ac.uk/981/.
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New near-infrared absorbing donor-acceptor chromophores have been investigated by varying the electron donating and accepting strength of the two halves of the molecule within wide limits. The dihydroperimidine, perimidine, Michler's ethylene and 1-decyl-2(1H)- methyl-benz[c, d]indolium iodide residues were examined as donor residues, and these were coupled to 4-nitrobenzenediazonium chloride to give monoazo dyes. The λmax values of these gave a qualitative indication of relative electron donor strengths, and the 1-ethyl-2-methylperimidine azo dyes proved to be the most bathochromic, being blue in colour. The dyes were amongst the most bathochromic monoazo dyes yet prepared containing the 4-nitrophenylazo residue. The N-alkyl-3-cyano-6-hydroxy-4-methyl-2-pyridone system was investigated as a potentially powerful electron acceptor system, and the 5-formyl and 5-nitroso derivatives were condensed with Michler's ethylene and 1-decyl-2(1H)-methyl-benz[c, d]indolium iodide to give new donor-acceptor dyes. The aza dyes prepared from the nitroso compounds proved to be the most bathochromic in accord with PMO theory and many were near-infrared absorbing. A series of near-infrared absorbing squarylium dyes with narrow, intense absorption bands at about 800nm were obtained by reacting squaric acid with 2,2-disubstituted dihydroperimidines. The first dyes of this type possessed poor organic solvent solubilities but, through modification of the 2,2-substituents of the dihydroperimidines it was possible to obtain squarylium dyes with good organic solvent solubility, this being a much sought after property of infrared dyes. Other squarylium dyes were obtained by the reaction of squaric acid with 1-ethyl-2-methylperimidine, Michler's ethylene and 1-decyl-2(1H)-methyl-benz[c, djindolium iodide. The latter two dyes absorbed in the infrared region at 809 and 900nm respectively in toluene. A modified procedure for the synthesis of croconic acid was developed, which enables the acid to be obtained in the anhydrous form readily. Reaction of croconic acid with 3-hydroxy-N, N-dialkylanilines afforded highly bathochromic dyes (λ max ca. 830nm). Reaction with 1- decyl-2(1H)-methyl benz[c, d]indolium iodide gave a croconium dye that absorbed beyond 1000nm. The reaction of 8-hydroxyjulolidine with croconic acid was particularly interesting as it occurred readily at room temperature. Thus it was possible to undertake a kinetic study of mechanistic aspects of the condensation reaction between croconic acid and arylamines. The results indicated that the optimum reaction conditions involved using a low proportion of an alcohol in a nonpolar aprotic solvent in the presence of a weak acid catalyst. Dyes were also obtained from the reaction of various electrophilic chlorine-substituted compounds with electron-donor aromatic residues, thus giving new donor-acceptor dyes, several of which were nearinfrared absorbing with low molecular masses and good organic solvent solubilities. The dyes were, however, strongly coloured due to their broad absorption bands which extended well into the visible region. The thermal and photochemical stabilities of representative examples of all the infrared dye classes prepared in this work have been examined, using standard procedures.
11
Howard, Daryl L., and n/a. "Hydrogen bonding in the near infrared." University of Otago. Department of Chemistry, 2006. http://adt.otago.ac.nz./public/adt-NZDU20060823.150321.
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OH-stretching spectra of various vapour phase species were recorded to investigate hydrogen bonding. The species studied include 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, acetylacetone, hexafluoroacetylacetone and the complex formed in the heterogeneous mixture of methanol and trimethylamine. The spectra range from the infrared, near infrared to visible wavelengths. The main focus of this study is in the near infrared region, in which the OH-stretching overtones are dominant.
The near infrared and visible spectrum of formic acid has been recorded to investigate coupling across bonds, specifically a resonance occurring between OH- and CH-stretching vibrations. The same resonance was also observed in the spectrum of 1,2-ethanediol. The spectra of deuterated isotopomers of formic acid and 1,2-ethanediol were recorded to experimentally verify the resonance.
The inherently weak nature of the vibrational overtone transitions required sensitive spectroscopic techniques to observe the spectra. The spectra were recorded with conventional long path length absorption spectroscopy and intracavity laser photoacoustic spectroscopy.
Anharmonic oscillator local mode calculations of the OH-stretching transitions were performed to simulate the observed spectra. These calculations require calculation of potential energy surfaces and dipole moment functions. Simulated spectra obtained with highly correlated ab initio methods and large basis sets have yielded the best agreement with observation.
12
Moss, Felix Mercer. "Face recognition using near infrared light /." Leeds : University of Leeds, School of Computer Studies, 2008. http://www.comp.leeds.ac.uk/fyproj/reports/0708/Moss.pdf.
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Chagas, Julio C. S. "Near-infrared absorption by atmospheric gases." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.365868.
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Miranda, Erasmus Couto B. de. "Atmospheric laser propagation at near infrared." Thesis, University College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267940.
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15
Ross, Graeme William. "Photorefractive processes at near infrared wavelengths." Thesis, University of Southampton, 1994. https://eprints.soton.ac.uk/399130/.
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This thesis presents the results of a three year study of the properties and applications of photorefractive materials. Attention is focused in particular on barium titanate, and experimental work examines the photorefractive processes and optical characteristics at near infrared wavelengths around 800nm - an important wavelength range compatible with solid state laser diodes. A comparison of properties is made between crystals of nominally undoped barium titanate and samples with impurity enhanced absorption in the red and near infrared which appear blue in colour. Throughout the thesis, photorefractive theory is developed to explain the experimental observations, and beam coupling experiments demonstrate energy exchange between laser beams within the photorefractive crystal in order to establish model parameters. Experiments investigating optical phase conjugation using the blue crystals demonstrate effective self-alignment and distortion correction, with high fidelity and good temporal and frequency stability. Wide wavelength response, laser diode compatibility, low power operation and highly efficient reflectivities of up to 76% at 1µm and 38% at 1.064µm make the new blue crystals promising for near infrared applications. Throughout, comparisons are drawn with the undoped crystal. Brightness enhancement schemes are also considered and a phase conjugate fibre laser demonstrated. Coupling of mutually incoherent laser beams is also reported at near infrared wavelengths with the demonstration of a self-aligning holographic interconnect behaving as a phase conjugate mirror with an effective reflectivity of 600%. Using laser diode sources, the wavelength tolerance of the coupling scheme is investigated and the effect of feedback during coupling examined.
16
Lan, Zhaojue. "Spectral tunable organic near-infrared photodetectors." HKBU Institutional Repository, 2020. https://repository.hkbu.edu.hk/etd_oa/771.
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Filter-free spectral tunable photodetectors (PDs) are critical for a plethora of applications in imaging, indoor light fidelity (Li-Fi), and light communications. The present band-selective light detection is realized by incorporating different optical filters with broadband inorganic semiconductor-based PDs. However, the use of the optical filters reduces the overall performance of these PDs and is not appliable in the emerging flexible and wearable applications. The rapid advancement of the organic semiconductors offers an exciting opportunity for the development of high-performance filter-free spectral tunable organic photodetectors (OPDs). The development of OPDs has attracted tremendous interests because of the tailored optoelectronic properties of the π-conjugated organic semiconductors and the solution fabrication process of the OPDs. Apart from the rapid progresses made in improving the responsivity and detectivity of OPDs, the spectral properties of OPDs also receive intense attention. This Ph.D. research work has been focused on developing a universal strategy to achieve high-performance filter-free band-selective and spectral tunable OPDs. The correlation between the optical profile and responsivity spectrum of the novel OPDs with a bilayer photoactive layer has been investigated. It suggests that the responsivity spectrum of the OPDs can be effectively modulated by managing the optical profile in the bilayer and multilayer photoactive layer. A filter-free band-selective OPD model, comprising a bilayer shorter-wavelength light depletion layer/longer-wavelength light-absorbing layer architecture photoactive layer, has been developed. The depletion layer in the filter-free OPDs has a dual-function serving as a shorter-wavelength light-absorbing layer and a hole-transporting layer. The photodetection spectrum window of the filter-free band-selective OPDs, defined by the difference in wavelengths between the transmission cutoff of the shorter-wavelength light depletion layer and the absorption edge of the longer-wavelength light-absorbing layer, can then be tuned over the different wavelength ranges by using an appropriate combination of the shorter-wavelength light depletion layer and the longer-wavelength light-absorbing layer. A dual-mode OPD, having a trilayer visible light absorber/optical spacer/near-infrared (NIR) light absorber configuration photoactive layer, has been proposed. The dual-mode OPD exhibits electrically switchable NIR response operated under a reverse bias and visible light response operated under a forward bias. In the presence of NIR light, the trap-assisted charge-injection behavior at the organic/cathode interface in the OPDs operated under a reverse bias. The photocurrent is produced in the visible light-absorbing layer, enabled by the trap-assisted charge injection at the anode/organic interface under a forward bias. The developed filter-free band-selective OPDs and electrically switchable dual-mode OPDs provided an attractive alternative optical detection technology to the conventional panchromatic and single-mode OPDs. The spectral tunable photodetection thus demonstrated offers a promising option for new OPD applications.
17
Zhao, Shuyan. "Face analysis under near infrared illumination." Göttingen Cuvillier, 2008. http://d-nb.info/990811492/04.
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Williams, David James. "Near infrared spectroscopy in cerebrovascular disease." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426180.
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Houston, Jessica Perea. "Near infrared optical lymphography for cancer diagnostics." Diss., Texas A&M University, 2005. http://hdl.handle.net/1969.1/4807.
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A new molecular imaging modality has been developed to detect and locate positive axillary and sentinel lymph nodes non-invasively in breast cancer patients undergoing lymphoscintigraphy. The modality is based on fluorescent photon detection to locate the presence of indocyanine green (ICG) in the lymph subsequent to peritumoral injection of ICG into the breast. The imaging system consists of a gain-modulated intensified charge-coupled device (ICCD) camera, which captures low-intensity, near-infrared, and frequency-modulated photons. A four-fold âÂÂoptical lymphographyâ study was conducted to (1) examine fluorescence depth penetration and ICCD system accuracy at clinically relevant depths, (2) compare image quality of the ICCD system vs. conventional gamma imaging, (3) measure ICG pharmacokinetics in vivo, and (4) develop a clinical protocol while examining pre-clinical factors such as the outcome of combining ICG with sulfur colloids used in lymphoscintigraphy. The frequency-domain ICCD system was found to precisely detect modulation amplitude, IAC, and phase, ø, at depths up to 9 cm and with IAC accuracy less than 20% and ø less than 2ú using an 80-mW laser incident on phantoms having ranging tissue optical properties. Significant differences in the mean depth of penetration owing to 0.62-ns lifetime and 100-MHz frequency increases were detected. An in vivo optical vs. nuclear image quality comparison demonstrated statistically similar (ñ=0.05) target-to-background ratios for optical (1.4+/-0.3) and nuclear (1.5+/-0.2). Alternatively, resulting image signal-to-noise ratios (SNR) from the ICCD system were greater than that achieved with a conventional gamma camera (pvalue<<0.01). Analysis of SNR versus contrast showed greater sensitivity of optical over nuclear imaging for subcutaneous tumors. In vivo and rapid detection of ICG in the blood-stream of nude mice was accomplished with a home-built avalanche photodiode dynamic fluorescence measurement system. Intensity data upon i.v. injection were regressed with a pharmacokinetic model describing the partitioning of ICG from the blood to the surrounding tissues. ICG blood-clearance was detected approximately 15 min after injection. Lastly, a human subject protocol was written, practiced, and federally approved for the application of optical lymphography. Furthermore, ICG was unaffected when mixed with sulfur colloids thus supporting the feasibility for combining fluorescence imaging with lymphoscintigraphy in breast cancer patients.
20
Feulner, Georg. "A Near-Infrared Selected Galaxy Redshift Survey." Diss., lmu, 2004. http://nbn-resolving.de/urn:nbn:de:bvb:19-31099.
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Bahrami, Amir. "Carbon nanotubes as near infrared laser susceptors." Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/230112.
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The coupling efficiency of carbon nanotubes with near infrared laser radiation at 940nm wavelength was investigated. Nanotubes treated with different post processing methods were irradiated at different laser power intensities as dry samples and suspensions in water or ethanol. The interaction with the laser beam was measured and quantified based on the temperature increase in the samples as well as the amount of energy transmitted through them. Parallel experiments using carbon black revealed better performance of carbon nanotubes in terms of coupling efficiency and heat dissipation to their surroundings. It was found that most of the incident radiation on an individual carbon nanotube is absorbed, resulting in extreme local temperature increases proportional to the laser intensity, which can lead to instant tube oxidation in air. Such high heats are efficiently transferred to the material in immediate contact with the nanotubes, increasing its temperature very rapidly. The most intriguing results were obtained in the presence of water where the observations suggested, disintegration of carbon nanotubes with each laser pulse. It is shown that extremely high local temperatures vaporise the water in the immediate vicinity of a carbon nanotube and result in a water-gas reaction. It is further postulated that such effects can be achieved with laser beams at power intensities near the skin tissue's safe exposure thresholds, and therefore can potentially be used as a method of removing nanotubes from living tissue. This has advantages in providing an exit route for nanotubes whether introduced on purpose for reasons of medicine or therapy, or possibly, as a result of inadvertent exposure. Further studies on laser heating and transmission through different dry samples, highlighted that more crystalline structures such as that of a heat-treated nanotube, are more effective in causing extinction of the laser beam and a reduction in the transmitted beam intensity, however the tubes with more defects or with a length comparable to the radiation wavelength are very effective in converting the absorbed laser energy to heat. This effect is exacerbated when the laser beam is polarised parallel to the long axis of the carbon nanotubes. These heating effects were exploited to create welds in high density polyethylene using through transmission laser welding. The resultant welds showed better than or equal mechanical performance to welds made using industrial absorbers such as carbon black or Clearweld®.
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Zanotti-Fregonara, Carlo Luigi Maria. "Near infrared cathodoluminescence of III-V heterostructures." Thesis, Imperial College London, 1998. http://hdl.handle.net/10044/1/7230.
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Todd, Stephen Peter. "Near-infrared integral field spectroscopy with UIST." Thesis, University of Edinburgh, 2004. http://hdl.handle.net/1842/27542.
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UIST is a facility class near-infrared imager and spectrometer, built at the UK Astronomy Technology Centre (UKATC) in Edinburgh, and now in use at the UK Infrared Telescope (UKIRT). UIST operates at wavelengths of 1-5 μm, providing a variety of imaging and spectrometry modes. UIST is the first instrument to include a cryogenic deployable integral field unit (IFU), allowing integral field spectroscopy to be carried out over a 3.3 x 6.0 arcsec field of view using any of the grisms available for spectroscopy in UIST. The optical components of the image slicing IFU were tested and aligned on the bench before the IFU was integrated into UIST for cryogenic tests in the laboratory in Edinburgh and on the telescope. These tests included measurements of the image quality produced by the IFU and the transmission of the IFU relative to a slit of equivalent width as a function of wavelength, found to increase from 0.4 at 1 μm to 0.62 at 2.5 μm. When the seeing is poor and high spectral resolution is required the loss of light in the IFU may be significantly less than the slit-losses from a conventional slit. The conditions under which use of the IFU may be preferable to use of a silt are discussed. The data reduction methods used to automatically combine IFU observations with arc-lamp spectra, flat-field frames and standard-star spectra in order to transform the two-dimensional output of the IFU into a calibrated (x, y, l) datacube in near real-time and the procedures required to obtain the necessary calibration data are outlined. An example of one type of observation made possible by the IFU is shown by observations of H2 lines excited in bow-shocks in the outflow from a young star in the vicinity of the ultra-compact H II region G25.65-1.05, allowing measurement of the spatial variation of the excitation temperature in these shocks.
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Casselgren, Johan. "Road surface classification using near infrared spectroscopy." Licentiate thesis, Luleå : Luleå University of Technology, 2007. http://epubl.ltu.se/1402-1757/2007/42/LTU-LIC-0742-SE.pdf.
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Gragg, Jamie Loretta. "Synthesis of Near-Infrared Heptamethine Cyanine Dyes." Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/chemistry_theses/28.
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Carbocyanine dyes are organic compounds containing chains of conjugated methine groups with electron-donating and electron-withdrawing substituents at the terminal heterocycles of the general formula [R1-(CH)n-R2]+X-. The synthetic methodology and optical properties of carbocyanines will be discussed. This thesis consists of two parts: (A) synthesis and optical properties of novel carbocyanine dyes substituted with various amines and the synthesis of unsymmetrical carbocyanine dyes containing monofunctional groups for bioconjugation. (B) synthesis of heptamethine carbocyanine dyes to be used for image-guided surgery. In part A, the synthesis of carbocyanine dyes functionalized with various amines and studies of their optical properties with respect to absorbance, fluorescence, quantum yield and extinction coefficient will be presented. These property studies will aid in designing efficient dyes for future biomedical applications. Part A will also include a one pot synthesis of unsymmetrical carbocyanine dyes functionalized with mono carboxylic acid chains, useful for biomolecule (i.e. proteins, amino acids, etc.) conjugation. Part B will describe the synthesis of novel carbocyanine dyes to be used for cancer image-guided surgery. Cancers are thus far incurable diseases, i.e. there are no drugs currently available to cure cancer; however, by designing a dye to visualize tumor cells will greatly increase the efficiency of cancer removal and hopefully increase the survival rate of cancer patients. The dyes reported in this thesis are superior to commercially available dyes used to visualize and identify various tumors invisible to the naked eye of surgeons with regards to biodistribution and clearance through kidney filtration.
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Lystrup, Makenzie Brook. "Near infrared studies of Jupiter's upper atmosphere." Thesis, University College London (University of London), 2008. http://discovery.ucl.ac.uk/16743/.
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This thesis is an investigation of near infrared emissions from Jupiter’s upper atmosphere using observations from high-resolution spectrometers on two ground-based telescopes: the NASA Infrared Telescope Facility (IRTF) and the Keck II. Four studies are presented and discussed in terms of the energetics and dynamics of Jupiter’s upper atmosphere and its connection to the surrounding magnetosphere. The work based on the IRTF data investigates short time scale variability in Jupiter’s near infrared aurora and the effects of that variability on atmospheric heating by examining fluctuations in the velocity of the ion winds in the southern auroral region. These velocities are derived from the Doppler shifting of H3+ emission lines. This thesis presents the highest quality data of Jupiter's near infrared aurora available to date, from the 10-metre Keck II telescope. Many emission features are identified that have not previously been observed outside the laboratory and-emission from the highest reaches of the upper atmosphere are observed for the first time with a ground-based telescope. Three studies based on these data are presented. A mid- to low-latitude study of H3+ emissions is presented, with profiles of intensities and column densities, and a compared with results from a global circulation model. H3+ and CH4 emissions are employed in a study of Jupiter's northern and southern auroral regions; profiles of rotational and vibrational temperatures, column densities, and total emission are presented. Finally, a new method for deriving vertical ion density and temperature profiles in Jupiter's auroral regions is developed. Such profiles have never been recorded and it was previously thought that such vertical profiles in Jupiter’s upper atmosphere could not be made from ground-based observations, but only from spacecraft data. Profiles derived from this new method are presented in the study.
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Perry, William Stephen. "Near infrared luminescence of D-F hybrids." Thesis, University of Manchester, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.496694.
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Near-IR emitting lanthanide chelates are of increasing interest as biological imaging agents as a consequence of the transparency of biological tissue to near-IR radiations coupled with the fact that low energy absorbing chromophores can be used to sensitise near-IR lanthanide based emission. Metal complexes containing polypyridine ligands have low energy ³MLCT states suitable for populating the emissive states of near-IR emitting lanthanide ions. This thesis describes the synthesis and photophysical properties of a series of kinetically stable lanthanide complexes covalently linked to transition metal complexes.
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Khanzadyan, T. "The near-infrared tracks of protostellar outflows." Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273151.
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Minchin, Nigel Robert. "Near-infrared imaging polarimetry of bipolar nebulae." Thesis, University of Hertfordshire, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.293286.
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Harris, Sean E. "Near infrared lymphatic mapping in thoracic malignancies." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12115.
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Thesis (M.A.)--Boston UniversityLung cancer is the leading cause of all cancer deaths in men and women combined, killing more than 150,000 patients per year. Lymph node status is the best predictor of survival in patients with surgically resectable lung cancer. The 5 year survival rates for node negative (N0), hilar node positive (N1), and mediastinal node positive (N2) disease is 53.8%, 26.3%, and 20.8%, respectively. Accurate staging of the disease will lead to the most effective adjuvant therapy strategy. However, routine pathologic analysis of sampled lymph nodes underestimates the prevalence of metastatic disease. Patients with missed metastatic disease do not receive proper treatment which likely contributes to the high recurrence rate and poor 5 year survival of lung cancer patients. Detection of lymph nodes at highest risk for harboring metastatic disease (i.e. sentinel lymph nodes (SLN)) may permit more intensive histologic analysis to detect occult disease. Presently there is no safe and reliable method for detecting SLNs. The overall objective of this project was to identify the SLNs and treat them. To do this, we looked at the feasibility of using indocyanine green (ICG) and near infrared (NIR) imaging in a minimally invasive video assisted thoracic surgery procedure to identify the SLNs in patients with suspected Stage I/II non small cell lung cancer (NSCLC). Previous attempts at SLN identification in patients with NSCLC using radioisotopes and blue dyes have been ineffective. ICG and NIR imaging for identification of SLNs has become standard of care in both melanoma and breast cancer. We looked to extend this technology to NSCLC. Patients were given an intraparenchymal, peritumoral injection of ICG and imaged with a NIR camera noting lymphatic migration, time to SLN identification, number of SLNs, and lymph node station. Our results demonstrated the increased rate of SLN identification over the previous studies. [TRUNCATED]
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Wang, Yazhong. "Stacked Dual Narrowband Organic Near-Infrared Photodetectors." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-139592.
Full textAbstract:
Compared with the detector devices made of inorganic semiconductors, organic photodetectors are granted with additional strengths, such as flexibility, high scalability and bio-compatibility. However, in the family of organic optoelectronic devices, the detectors that are capable of detecting photons at two or multiple specific wavelengths are still missing. Such photodetectors are highly interesting because they could identify the target objects or materials much more precisely by detecting the reflected, transmitted or emitted photons at two or multiple characteristic wavelengths. In this thesis project, the optical simulations using Transfer Matrix Method (TMM) were performed on the organic devices to achieve the dual wavelength narrowband detection in the near-infrared (NIR) spectral range of 700 ~ 1100 nm. The devices use the fact that, at the interface of the blended organic electron donating and accepting materials, the charge-transfer (CT) states with the transition energies that are lower than the optical gap of the neat materials are formed. Combined with a Fabry-Perot resonant cavity, the CT absorption can be dramatically enhanced at certain wavelengths. The simulation results show that the two detection wavelengths can be tuned independently from 650 to 1100 nm. The spectral resolution (full with at half maximum - FWHM) of the detection bands varies between 10 and 30 nm. The simulated external quantum efficiency (EQE) is ~35% at 700 nm and ~10% at 1000 nm, respectively. A possible application of such photodetectors is for example moisture detection, where two of the characteristic absorption peaks of water are located at around 750 and 960 nm. By optimizing the thickness of the two photo-absorbing layers in a tandem device structure, the detection bands can be tuned to match with those two wavelengths for simultaneous and precise detection.
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Kelly, Douglas Michael. "Near-infrared spectroscopy as an astrophysical tool." Diss., The University of Arizona, 1992. http://hdl.handle.net/10150/185983.
Full textAbstract:
Recent improvements in infrared detector arrays make it possible for the first time to conduct detailed spectroscopic studies of a complete range of objects in the 0.9-1.35 μm region. In this dissertation, I examine the 0.9-1.35 μm spectra of planetary and proto-planetary nebulae, M dwarfs, young stellar objects, Seyfert galaxies, an H II region, and a Wolf-Rayet star. Line identifications are made for each of these objects, and extensive line lists are presented. I also investigate what the lines can tell us about each object. The 0.9-1.35 μm spectrum of the proto-planetary nebula AFGL 618 is dominated by recombination lines, low-ionization, shock-excited lines, and thermal and fluorescent H₂ lines. We use ratios of forbidden lines to show that there are two distinct physical regions in the lobes of AFGL 618, including one which must have been excited by shocks. We also show that the H₂ lines in the 0.9-1.35 μm region are ideal for detecting low levels of fluorescent H₂ emission, even when a strong thermal component is present. We present 0.6-1.5 μm spectra for M dwarfs ranging from M2 through M9. These spectra are compared with recent theoretical models, and a temperature scale is determined. In late-M dwarfs, the shape of the infrared spectrum and the depth of the 1.35 μm H₂O feature are good temperature indicators. The temperatures we derive for the M dwarfs are higher than the temperatures found in earlier studies and are in closer agreement with theoretical tracks of the lower main sequence. We present 0.9-1.35 μm spectra for 7 young stellar objects. These objects exhibit a wide variety of behavior, including strong fluorescent emission. We show that the infrared spectra can be used to study all of the regions that are detected with visible and red spectra. As a result, 0.9-1.35 μm spectroscopy should be quite useful for studying heavily embedded sources. The 0.9-1.35 μm spectra of high-excitation objects include a number of distinctive features including He II lines, several high ionization lines, and very strong (S III) lines. We find that the excitation level of a source can be estimated based on these features alone.
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Gresham, Christopher Allen 1965. "Near-infrared spectroscopy utilizing array detector technology." Diss., The University of Arizona, 1998. http://hdl.handle.net/10150/282690.
Full textAbstract:
A near-infrared spectrometer incorporating solid-state design applicable for industrial quantitative/qualitative process monitoring analysis is presented. The solid-state near-infrared spectrometer provides inherent wavelength stability necessary for long term calibration accuracy. The spectrometer consists of a 24 volt, 10 watt quartz-halogen-tungsten regulated source with optical feedback. Wavelength dispersion was accomplished using a 50 μm entrance slit, f/4, 0.25 meter spectrograph equipped with astigmatism correcting toroidal mirrors and a 300 gr/mm plane reflectance ruled grating blazed for 2000 nm peak efficiency. A 1024 element backside- illuminated Schottky-barrier PtSi photodiode array detector with wavelength response from 900-5000 nm and peak quantum efficiency of 8% at 1100 nm was operated using cryogenic cooling to reduce dark response. A readout rate of 31.25 kHz produced 41 msec integration time per array read. The readout was digitized to 16 bit resolution for subsequent data storage. This system demonstrated 1.5 nm spectral bandpass, 3 orders linear dynamic range and typical baseline rms noise level of 10⁻⁴ a.u. Using this system, quantitative/qualitative chemical analyses were performed focusing on industrial analytical chemical applications. Simultaneous quantitative multcomponent xylene isomer mixtures analysis was achieved using the solid-state near-infrared spectrometer coupled with partial least squares regression multivariate data treatment. The results demonstrate an absolute accuracy of ± 0.05, ±0.12 and ±0.09% w/v for o-, m- and p-xylene isomers respectively. In a separate chemical study, qualitative classification analysis of specially denatured alcohol mixtures was successfully performed on 53 validation samples using 35 reference samples belonging to 12 classes. The validation set included mixture sample types used for model calibration as well as others composed of compounds not used for model calibration. The multivariate cluster classification method using principal components was employed to correctly classify 100% of the validations samples analyzed. The solid-state near-infrared spectrometer was also applied for direct reaction monitoring of the O-H overtone absorption band at 1411 nm for the reaction between triisopropyl-chlorosilane and methanol. The results illustrated the utility of near-infrared functional group monitoring of reactions at relatively high concentrations for information elucidation concerning reaction initiation and completion.
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Miller, Charles Edward. "Analysis of synthetic polymers by near-infrared spectroscopy /." Thesis, Connect to this title online; UW restricted, 1989. http://hdl.handle.net/1773/11580.
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Singh, Baljinder. "Visible and near-infrared spectroscopic analysis of potatoes." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=84074.
Full textAbstract:
The potential of different spectroscopic techniques for evaluating potato (Solanum tuberosum L.) quality was investigated. Spectral data in the wavelength range of 400-1750 nm were used to develop quality prediction models. The Partial Least Squares (PLS) regression was used for predicting the water content in potato samples. Water content was predicted with R2 ≥ 0.938.A further study was conducted to find the best wavelengths for predicting water content using two methods, PLS and multiple linear regression. Wavelength ranges of 910-1020, 1129-1211, 1363-1403 nm were selected for samples without skin, while 700-900, 930-1050, 1100-1300, 1400-1550 nm were selected for samples with-skin. Weight prediction models were established using the predicted water content.
Visible spectroscopy was used for classifying shriveled and non-shriveled potatoes. The wavelength ranges best suited to such a classification were those of 442-452, 456-466, 641-651, and 684-694 nm, with accuracies as high as 94.28% and as low as 80%.
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Froning, Cynthia Suzanne. "The near-infrared properties of compact binary systems /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Loudet, Aurore. "Design of novel dyes towards the near-infrared." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2449.
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Jacob, Rainer. "Scanning near-field infrared microspectroscopy on semiconductor structures." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-68317.
Full textAbstract:
Near-field optical microscopy has attracted remarkable attention, as it is the only technique that allows the investigation of local optical properties with a resolution far below the diffraction limit. Especially, the scattering-type near-field optical microscopy allows the nondestructive examination of surfaces without restrictions to the applicable wavelengths. However, its usability is limited by the availability of appropriate light sources. In the context of this work, this limit was overcome by the development of a scattering-type near-field microscope that uses a widely tunable free-electron laser as primary light source. In the theoretical part, it is shown that an optical near-field contrast can be expected when materials with different dielectric functions are combined. It is derived that these differences yield different scattering cross-sections for the coupled system of the probe and the sample. Those cross-sections define the strength of the near-field signal that can be measured for different materials. Hence, an optical contrast can be expected, when different scattering cross-sections are probed. This principle also applies to vertically stacked or even buried materials, as shown in this thesis experimentally for two sample systems. In the first example, the different dielectric functions were obtained by locally changing the carrier concentration in silicon by the implantation of boron. It is shown that the concentration of free charge-carriers can be deduced from the near-field contrast between implanted and pure silicon. For this purpose, two different experimental approaches were used, a non-interferometric one by using variable wavelengths and an interferometric one with a fixed wavelength. As those techniques yield complementary information, they can be used to quantitatively determine the effective carrier concentration. Both approaches yield consistent results for the carrier concentration, which excellently agrees with predictions from literature. While the structures of the first system were in the micrometer regime, the capability to probe buried nanostructures is demonstrated at a sample of indium arsenide quantum dots. Those dots are covered by a thick layer of gallium arsenide. For the first time ever, it is shown experimentally that transitions between electron states in single quantum dots can be investigated by near-field microscopy. By monitoring the near-field response of these quantum dots while scanning the wavelength of the incident light beam, it was possible to obtain characteristic near-field signatures of single dots. Near-field contrasts up to 30 % could be measured for resonant excitation of electrons in the conduction band of the indium arsenide dotsDie optische Nahfeldmikroskopie hat viel Beachtung auf sich gezogen, da sie die einzige Technologie ist, welche die Untersuchung lokaler optischer Eigenschaften mit Auflösungen unterhalb der Beugungsgrenze ermöglicht. Speziell die streuende Nahfeldmikroskopie erlaubt die zerstörungsfreie Untersuchung von Oberflächen ohne Einschränkung der verwendbaren Wellenlängen. Die Nutzung ist jedoch durch das Vorhandensein entsprechender Lichtquellen beschränkt. Im Rahmen dieser Arbeit wurde diese Beschränkung durch Entwicklung eines streuenden Nahfeldmikroskops überwunden, das einen weit stimmbaren Freie-Elektronen-Laser als primäre Lichtquelle benutzt. Im theoretischen Teil wird gezeigt, dass ein optischer Kontrast erwartet werden kann, wenn Materialien mit unterschiedlichen Dielektrizitätskonstanten kombiniert werden. Es wird hergeleitet, dass diese Unterschiede in unterschiedlichen Streuquerschnitten für das gekoppelte System aus Messkopf und Probe resultieren. Diese Streuquerschnitte definieren die Stärke des Nahfeldsignals, welches auf unterschiedlichen Materialien gemessen werden kann. Ein optischer Kontrast kann also erwartet werden, wenn unterschiedliche Streuquerschnitte untersucht werden. Dass dieses Prinzip auch auf übereinander geschichtete oder sogar verborgene Strukturen angewendet werden kann, wird in dieser Doktorarbeit an zwei Probensystemen experimentell gezeigt. Im ersten Beispiel wurden die unterschiedlichen Dielektrizitätskonstanten durch örtliches Ändern der Ladungsträgerdichte in Silizium durch Bor-Implantation erreicht. Es wird gezeigt, dass die Dichte der freien Ladungsträger an Hand des optischen Kontrastes zwischen implantiertem und reinem Silizium ermittelt werden kann. Zu diesem Zweck wurden zwei unterschiedliche Ansätze verwendet, ein nicht-interferometrischer mittels variabler Wellenlängen und ein interferometrischer mit einer konstanten Wellenlänge. Weil diese Techniken gegensätzliche Informationen liefern, können sie genutzt werden, um die effektive Ladungsträgerdichte quantitativ zu bestimmen. Beide Ansätze lieferten konsistente Resultate für die Trägerdichte, welche sehr gut mit den Vorhersagen der Literatur übereinstimmt. Während die Strukturen im ersten Beispiel im Mikrometer-Bereich lagen, wird die Möglichkeit, verborgene Nanostrukturen zu untersuchen, an Hand einer Probe mit Indiumarsenid Quantenpunkten demonstriert. Diese sind von einer dicken Schicht Galliumarsenid bedeckt. Zum ersten Mal wird experimentell gezeigt, dass Übergänge zwischen Elektronenzuständen in einzelnen Quantenpunkten mit Nahfeldmikroskopie untersucht werden können. Durch die Messung der Nahfeld-Antwort der Quantenpunkte unter Änderung der Wellenlänge des eingestrahlten Lichtes war es möglich, charakteristische Nahfeld-Signaturen der einzelnen Quantenpunkte zu erhalten. Nahfeld-Kontraste bis zu 30 Prozent konnten für die resonante Anregung der Elektronen im Leitungsband der Indiumarsenid Punkte beobachtet werden
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Jacob, Rainer. "Scanning near-field infrared microspectroscopy on semiconductor structures." Helmholtz-Zentrum Dresden-Rossendorf, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-85330.
Full textAbstract:
Near-field optical microscopy has attracted remarkable attention, as it is the only technique that allows the investigation of local optical properties with a resolution far below the diffraction limit. Especially, the scattering-type near-field optical microscopy allows the nondestructive examination of surfaces without restrictions to the applicable wavelengths. However, its usability is limited by the availability of appropriate light sources. In the context of this work, this limit was overcome by the development of a scattering-type near-field microscope that uses a widely tunable free-electron laser as primary light source.
In the theoretical part, it is shown that an optical near-field contrast can be expected when materials with different dielectric functions are combined. It is derived that these differences yield different scattering cross-sections for the coupled system of the probe and the sample. Those cross-sections define the strength of the near-field signal that can be measured for different materials. Hence, an optical contrast can be expected, when different scattering cross-sections are probed. This principle also applies to vertically stacked or even buried materials, as shown in this thesis experimentally for two sample systems.
In the first example, the different dielectric functions were obtained by locally changing the carrier concentration in silicon by the implantation of boron. It is shown that the concentration of free charge-carriers can be deduced from the near-field contrast between implanted and pure silicon. For this purpose, two different experimental approaches were used, a non-interferometric one by using variable wavelengths and an interferometric one with a fixed wavelength. As those techniques yield complementary information, they can be used to quantitatively determine the effective carrier concentration. Both approaches yield consistent results for the carrier concentration, which excellently agrees with predictions from literature. While the structures of the first system were in the micrometer regime, the capability to probe buried nanostructures is demonstrated at a sample of indium arsenide quantum dots. Those dots are covered by a thick layer of gallium arsenide. For the first time ever, it is shown experimentally that transitions between electron states in single quantum dots can be investigated by near-field microscopy. By monitoring the near-field response of these quantum dots while scanning the wavelength of the incident light beam, it was possible to obtain characteristic near-field signatures of single dots. Near-field contrasts up to 30 % could be measured for resonant excitation of electrons in the conduction band of the indium arsenide dots.
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Alves, de Oliveira Catarina. "Near infrared variability phenomena in young stellar objects." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-91102.
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Hope, Matthew J. "Near-infrared spectroscopic diagnosis of acute compartment syndrome." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/24707.
Full textAbstract:
Hypothesis: NIRS can be used as a reliable method for the detection of an acute compartment syndrome. Methods: 1) A prospective clinical trial of 102 patients at risk of an ACS. Continuous invasive pressure and NIRS measurements were recorded and compared. 2) A porcine model of 15 animals to investigate the influence of a subcutaneous and intra-muscular haematoma on the ability of NIRS to detect an ACS. 3) Two studies of volunteer subjects investigated the relationship between adipose thickness, measured by ultrasound, and the values of StO2 provided by NIRS. Results: 1) Correlation was observed between StO2 and compartment pressure. Calculating the StO2 difference between the injured and un-injured limbs reduced the inter-patient variability. 2) The presence of a sub-cutaneous haematoma increased the StO2 value. 3) The StO2 value over the leg correlated with adipose thickness and total tissue haemoglobin. Conclusions: Inter-patient variations in StO2 made interpretation of clinical data difficult. The presence of a subcutaneous haematoma could cause a false negative diagnosis of ACS by elevating the StO2 value. The quantitative use of NIRS to measure StO2 could be improved by calibrating for adipose thickness.
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Mary, Rose. "Compact near-infrared 3-dimensional channel waveguide lasers." Thesis, Heriot-Watt University, 2014. http://hdl.handle.net/10399/2911.
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This thesis presents the development of ultrafast near-infrared (NIR) waveguide laser sources, through the fabrication of waveguides in Yb-doped bismuthate glass using ultrafast laser inscription (ULI). An integrated linear cavity waveguide laser is demonstrated in the glass with output powers of 163 mW and a slope efficiency of 79%. The laser performance is comparable to bulk systems while providing additional advantages in terms of low threshold ~35 mW and system compactness. The simultaneous achievement of low propagation losses and preservation of the fluorescence properties of Yb ions after the ULI process is key to the outstanding laser performance. Based on the current interest in ultrafast laser development using graphene as a saturable absorber (SA), a systematic study of nonlinear absorption in graphene is presented. The nonlinear optical characterisation of graphene at the wavelengths of 1 μm and 2 μm contributes to the experimental evidence for the wavelength independent absorption saturation in the material. Ultrashort pulse generation from the Yb-doped bismuthate waveguide laser is investigated using SAs based on semiconductor technology and carbon nanostructures. The quasi-monolithic waveguide laser, employing a graphene SA generated ~485 mW output power with a slope efficiency of 49%. The laser generated ~1 ps pulses in a Q-switched mode-locked regime, with the mode-locked pulses measuring a high repetition rate of 1.5 GHz. Ultrafast laser development is also investigated based on a novel evanescent-wave mode-locker device, fabricated by ULI. The device consists of an orthogonal waveguide with the right-angle positioned along its angled facet. The substrate is converted into a mode-locker by depositing carbon nanotube SA at the angled facet. Mode-locked operation is demonstrated by incorporating the substrate in an Er-doped ring laser, generating ~800 fs pulses at 26 MHz. Some preliminary work is done to replicate the device design in an active gain medium, namely, Yb-doped bismuthate glass, for the development of compact laser sources.
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Salvatore, Danielle Aline. "Amorphous electrocatalysts formed by near-infrared-driven decomposition." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/54496.
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The splitting of water into hydrogen and oxygen is widely viewed as the most sustainable option for storing energy produced by intermittent renewable energy sources such as solar or wind. Economically feasible large-scale deployment of this type of system requires the discovery of efficient electrocatalysts, particularly for the kinetically slow oxygen evolution reaction (OER). Transition metal oxides are the most durable and active water oxidation catalysts, and there is a growing body of evidence showing amorphous metal oxide films mediate the OER more efficiently than the crystalline phases of the same compositions. Notwithstanding, there is a limited set of fabrication methods available for making amorphous films, particularly in the absence of a conducting substrate. I introduce herein a scalable preparative method for accessing oxidized and reduced phases of amorphous films that involves the efficient decomposition of molecular precursors, including simple metal salts, by exposure to near-infrared (NIR) radiation. The NIR-driven decomposition process provides sufficient localized heating to trigger the liberation of the ligand from solution-deposited precursors on substrates, but insufficient thermal energy to form crystalline phases. This method provides access to state-of-the-art electrocatalyst films, as demonstrated herein for the electrolysis of water, and extends the scope of usable substrates to include non-conducting and temperature-sensitive platforms. Because crystalline ruthenium oxide is one of the most efficient electrocatalysts in acidic media, it would be highly advantageous to be able to readily access the amorphous phase of the material. I also document two facile preparation techniques for accessing amorphous ruthenium oxide, a state-of-the-art electrocatalyst. The formation of amorphous ruthenium oxide films is triggered by the decomposition of a film of spin-cast molecular ruthenium precursors on conducting glass by either ultraviolet (UV) and near infrared (NIR) light.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Higgs, Tim D. "Optical and near infrared properties of massive galaxies." Thesis, University of Portsmouth, 2014. https://researchportal.port.ac.uk/portal/en/theses/optical-and-near-infrared-properties-of-massive-galaxies(de9bfef2-67bd-45f1-bd7d-d54e08566237).html.
Full textAbstract:
In this thesis, we present a comparison of the evolution of the massive galaxies in the 7.8Gyr since redshift z=1 to the evolution predicted from galaxy formation models. Observing the most massive galaxies in the Universe at high redshift is challenging due to their red colours, owing to both their intrinsically red Spectral Energy Distributions (SEDs) and their redshift. In Chapter 1, We produce a method using catalogue-level data to produce matched aperture photometry for the SDSS and UKIDSS surveys in order to extend the wavelength coverage of a sample of galaxies in order to improve the precision with which models can be fitted to photometric data for these high redshift galaxies. Our matched photometry has consistent colours with those of the full processing of SDSS+UKIDSS images performed by the GAMA survey, and produces magnitudes within ∼0.1 magnitudes of the GAMA photometry for all galaxies. This is reduced to within 0.04 magnitudes when all blended sources are excluded. We compute stellar masses by fitting a Maraston et al. (2009) LRG model to both our derived photometry and that of the GAMA processing, and find that our photometry’s best fit stellar masses are within ∼0.2 dex of that which comes from the GAMA photometry, demonstrating that the method is consistent with that of a full processing, and that it is possible to quickly compute matched photometry for large area surveys of complimentary wavelength coverage. This is of vital importance for upcoming surveys e.g. DES, VISTA, EUCLID etc. Fitting Stellar Population Models to galaxy photometry is a widely used technique in order to convert from observables (colours, magnitudes) to physical properties (mass, absolute magnitude, age). In spite of their widespread use, the optical and Near Infrared (NIR) properties of stellar population models are still subject to debate. Two of the most commonly used models are those of (Maraston, 2005) (M05) and (Bruzual & Charlot, 2003) (BC03), which can differ greatly in the NIR due to the M05 models’ inclusion of the TP-AGB phase, which was neglected for BC03 models. We explore the ability of these models to reproduce measured optical+NIR properties of galaxies in Chapter 3. We produce matched optical+NIR photometry for the subsample of the galaxies surveyed by Zibetti et al. (2013) (Z13) which lie within the UKIDSS imaging area in an attempt to reproduce the findings of Z13, who conclude that their optical and NIR spectroscopy is better fit by models from Bruzual & Charlot (2003) than similar models from Maraston et al (2005). We compare the observed optical+NIR Spectral Energy Distributions (SEDs) to those of BC03 and M05 models, as well as the approximate Z13 NIR fluxes. Z13 found that M05 models fitted to the optical data and extrapolated into the NIR displayed excess flux in the NIR relative to the data, and BC03 models are better at reproducing the data. However, we show that our data is consistent with both sets of models, and on average brighter in the NIR than that of Z13. We also compare the strength of spectral features in the optical to rest frame optical and optical-NIR colours, and show that our set of Composite Stellar Population (CSP) models agree well with data, with a preference for the M05 models, showing the validity of using these models on massive galaxies. A measurement of the Stellar Mass Function (SMF) of galaxies is a powerful tool in detecting evolution of the galaxy population. With a statistically complete sample of a galaxy population down to a given stellar mass, it is possible to calculate a statistically complete SMF down to this mass. Comparison of the shape of this SMF to that of a similar sample over a different redshift interval allows the evolution of galaxies over this redshift interval to be calculated, in order to determine whether these galaxies are forming stars, merging or simply passively evolving. For this purpose, in 4 compute matched SDSS+UKIDSS photometry for the AA omega KIDSS SDSS (AUS) survey. This is a 145.416 deg² area survey of Luminous Red Galaxies (LRGs) from redshift z∼0.5 to z∼1 located within Stripe 82. We fit this photometry to a Maraston et al. (2009) Luminous Red Galaxy (LRG) template to give stellar masses, and scale masses according to the magnitude difference between the matched photometry and the SDSS model photometry in order to produce “total” stellar masses. We produce a volume-weighted SMF for the survey, and find that our SMF is consistent with the Maraston et al. (2013) SMF from the BOSS survey, meaning that the most massive galaxies in the universe are evolving passively from z=1 to the present day, which is a challenge to hierarchical models of galaxy formation. Comparison of observed SMFs to those produced by galaxy formation models is a method of testing the ability of the models to reproduce the evolution displayed by the real galaxy population. This is therefore a test of the physics included within the models, with the level of agreement between the simulation and the real galaxy SMF being indicative of whether the modelling has incorporated all the processes in action in the real universe. In order to test the ability of the state of the art semi analytical models of Henriques et al. (2013) (H13 hereafter), we compare SMFs of the simulated galaxies to those of the AUS and BOSS surveys in Chapter 5. The H13 galaxies were tailored via the application of both the AUS and BOSS colour and magnitude cuts, and SMFs calculated within lightcones of the same area as the surveys in order to compare equal volumes. Our findings extend the conclusions of Maraston et al. (2013), namely that the most massive galaxies in the simulations are not sufficiently massive to agree with the observed galaxy population at this redshift. By extending this analysis to redshift z∼1, we can confirm that the discrepancy is larger at higher redshift, with the difference between the most massive galaxies in the simulations and those observed being log(ΔM/M⊙) ≃0.2 at z≃0.6–0.7, whereas going beyond this to the range z≃0.7–1 the difference becomes log(ΔM/M⊙) ≃0.25, as can be seen in Figure 5.6, which demonstrates that the simulations are failing to either form, or assemble, the mass quickly enough to reproduce the observations. Instead, the simulations continue to assemble mass through to low redshift at a higher rate than is seen in the galaxy SMF. These discrepancies may indicate that the physics of the simulations is not fully accounting for the real processes in the Universe,and that we do not yet have a model capable of reproducing the galaxy population in the real universe. Clearly semi analytical galaxy simulations need to be modified in order to reproduce the observations, before being further challenged by upcoming spectroscopic surveys of galaxies at redshifts as high as z=2 eg. eBoss, DESI.
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Yousefi, Gharebaghi Farzad. "Near Infrared (NIR) Spectroscopic Assessment of Engineered Cartilage." Diss., Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/477078.
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BioengineeringPh.D.
Articular cartilage has limited intrinsic healing capacity due to its dense and avascular structure. Clinical approaches have been developed to address the limitations associated with the poor ability of articular cartilage to regenerate. Current clinically approved techniques, however, can result in repair tissue that lacks appropriate hyaline cartilage biochemical and biomechanical properties, which lead to uncertain long-term clinical outcomes. Using tissue engineering strategies and a range of scaffolding materials, cell types, growth factors, culture conditions, and culture times, engineered tissues have been produced with compositional and biomechanical properties that approximate that of native tissue. In these studies, a considerable number of samples are typically sacrificed to evaluate compositional and mechanical properties, such as the amount of deposited collagen and sulfated glycosaminoglycan (sGAG) in the constructs. The number of sacrificed samples, as well as the amount of time and resources spent to evaluate the sacrificed samples using current gold standards, motivates an alternative method for evaluation of compositional properties. Vibrational spectroscopy, including infrared, has been considered as an alternative technique for assessment of tissues over the last 15-20 years. Infrared spectroscopy is based on absorbance of infrared light by tissue functional groups at specific vibrational frequencies, and thus, no external contrast is required. Vibrational spectroscopy is typically performed in two frequency regions, the mid infrared region (750-4000 cm-1), where penetration depth is limited to approximately 10 microns, and the near infrared (NIR) region (4000-12000 cm-1). In the NIR region, penetration of light is on the order of millimeters or centimeters, which makes it ideal for obtaining data through the full depth of engineered constructs. Here we employ NIR spectroscopy to nondestructively monitor the development of tissue-engineered constructs over culture period.
Temple University--Theses
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Taylor, Helen Ruth, University of Western Sydney, and School of Food Sciences. "The evaluation of wort by near infrared spectroscopy." THESIS_FFS_XXX_Taylor_H.xml, 2001. http://handle.uws.edu.au:8081/1959.7/748.
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Near infrared spectroscopy (NIS) has been used routinely for many years for the measurement of grain protein and moisture in plant breeding programmes. Investigation as to the applicability of NIS to the identification from a barley breeding programme of the progeny with high malting quality potential was carried out over several harvests. The project concentrated on the determination of correlations between Hot Water Extract, Total Soluble Nitrogen, and Free Alpha Amino Nitrogen contents of worts (the extract of malt used to make beer) and NIR transmission data using the multivariate method of partial least squares regression. The correlation coefficients, for both calibration and prediction data sets, were significant and the standard error of prediction was similar to that obtained in the standard methods in the first year, but were unsatisfactory in the second. The instrument chosen for the study gave satisfactory correlations for the purpose of selection in the intermediate generations of the breeding programme with errors similar to the analytical methods, as long as a very wide range of calibration samples were collected from more than one harvest. It was shown that the use of an NIR spectrophotometer as a selection tool for malting quality within a barley breeding programme would not be sufficient to justify investment in this type of instrument for this purpose alone.Master of Science (Hons)
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Elfving, Anders. "Near-infrared photodetectors based on Si/SiGe nanostructures." Doctoral thesis, Linköping : Surface and Semiconductor Physics, Linköping University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5909.
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Lenorzer, Annique. "Near-infrared spectroscopic analysis of hot massive stars." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2004. http://dare.uva.nl/document/91869.
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Hearty, Frederick R. "Near infrared study of shrouded active galactic nuclei." Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3273659.
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Kriegel, Ilka. "Near-infrared plasmonics with vacancy doped semiconductor nanocrystals." Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-164558.
Full textAbstract:
Plasmonics with heavily doped semiconductor nanocrystals (NCs) is an emerging field in NC science. However, impurity doping of NCs remains far from trivial and is, as yet, dominated by a low chemical control over the incorporated dopant atoms. An appealing alternative is vacancy doping, where the formation of vacancies in the structure is responsible for an increased carrier density and elegantly circumvents the issues related to impurity doping. Due to high carrier densities of around 10^21cm^(-3) localized surface plasmon resonances (LSPRs) in the near infrared (NIR) are expected, and as such highlighted to close the gap between conventionally doped NCs and noble metal nanoparticles. Copper chalcogenide NCs, namely copper sulfide (Cu2-xS), copper selenide (Cu2-xSe), and copper telluride (Cu2-xTe), are an attractive example of vacancy doped semiconductor NCs, with spectra dominated by intense NIR resonances. Within this study thorough experimental evidence has been given to prove the plasmonic nature of those NIR resonances. By presenting typical plasmonic characteristics, such as refractive index sensitivity of the LSPR, its intrinsic size dependence, plasmon dynamics, or interparticle plasmon coupling, the LSPRs in copper chalcogenide NCs have unambiguously been identified. The chemical nature of vacancy doping turns out to deliver an additional, highly attractive means of control over the LSPR in vacancy doped copper chalcogenide NCs. Through chemical tailoring of the copper vacancy density via controlled oxidation and reduction, as shown in this study, a reversible tuning of the LSPR over a wide range of frequencies in the NIR (1000-2000 nm) becomes feasible. This highlights copper chalcogenide NCs over conventional plasmonic materials. Notably, the complete suppression of the LSPR uncovers the excitonic features present only in the purely semiconducting, un-doped NCs and reveals the unique option to selectively address excitons and highly tunable LSPRs in one material (bandgap Eg~1.2 eV). As such, copper chalcogenide NCs appear to hold as an attractive material system for the investigation of exciton plasmon interactions. Indeed, a quenching of the excitonic transitions in the presence of the developing LSPR is demonstrated within this work, with a full recovery of the initial excitonic properties upon its suppression. A theoretical study on the shape dependent plasmonic properties of Cu2-xTe NCs reveals a deviation from the usual Drude model and suggests that the carriers in vacancy doped copper chalcogenide NCs cannot be treated as fully free. On the other hand, the Lorentz model of localized oscillators appears to account for the weak shape dependence, as observed experimentally, indicating an essential degree of localization of the carriers in vacancy doped copper chalcogenide NCs.
Taken together, this work delivers a huge step toward the complete optical and structural characterization of plasmonic copper chalcogenide NCs. The advantages of semiconductor NC chemistry have been exploited to provide access to novel plasmonic shapes, such as tetrapods that have not been feasible to produce so far. A precise size, shape and phase control presents the basis for this study, and together with a thorough theoretical investigation delivers important aspects to uncover the tunable plasmonic properties of vacancy doped copper chalcogenide NCs.