Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"wavelength shift"”.
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Temperature and strain sensing using rare earth fluorescence and Bragg gratings in optical fibres
… the fluorescence intensity ratio and the Bragg wavelength shift are investigated.
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Temperature -Invariant Photoluminescence and Gain Spectra of Strained Gallium -Indium -Arsenide Quantum Wires
… grown GaInAs QWR Fabry-Perot laser diode. The wavelength-shift rate of the gain spectra is ∼1.4 A/°C. These temperature stabilized gain spectra make the QWRs applicable to long-wavelength VCSELs. The temperature invariant gain spectra can be used to increase the light output power, …
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Reference interferometry techniques for nanodetection and biosensing
… the parallel Mach-Zehnder can detect resonant wavelength shifts of the microcavity down to hundreds of attometers, provided sufficient system stability. Furthermore, a cavity resonant wavelength shift detection sensitivity of 0.14 femtometers is observed experimentally with a loaded microsphere …
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Raman-based measurements of greenhouse activity of combustion flue gases
… causes the energy exchange and the corresponding wavelength shift during Raman scattering. In this work, Raman scattering spectrum and infrared emission intensity in CO2-containing atmospheric jets at various temperatures and concentrations were measured. The results show that there is a linear …
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Fibre gratings in novel optical fibres for applications in sensing
… current, causes a temperature induced Bragg wavelength shift.
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Plasmonic nanostructures and metamaterials for nanoscale light-matter interaction
… for ultrasensitive molecular sensing using the wavelength shift of their localized surface plasmon resonance. The effect of interparticle spacing and relative orientation of the nanocubes in the nanocube chains has also been analyzed. The band-edge lattice plasmon waves in plasmonic nanoantenna …
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Studying DNA-Directed Nanoassembly, Hybridization and Mismatch-Discrimination via Plasmon Scattering of Gold Nanoparticles
… structures, successfully correlated to the LSPR wavelength shift and the plasmon color change, showed that their homogeneous formations in bulk solution were influenced by parameters inherent to nAu and DNA. The progress of hybridization was monitored through the localized surface plasmon …
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Distributed Feedback Laser Biosensor in Microplate Format
… molding process was used to create subwavelength periodic grating structures, while a horizontal dipping process was used to apply a ~300 nm, dye-doped polymer film. In this work, the DFBLB emission wavelength, used to characterize the device uniformity, demonstrated a coefficient of …
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Bragg grating sensor interrogation using in-line, dual-mode fiber demodulators
… changes occurring on the grating induce a shift in the reflected wavelength and monitoring the wavelength shift provides a indication of the strength of the perturbation. Currently, the most basic Bragg grating demodulation system consists of monitoring the reflected wavelength with an …
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Monitoring of fermentation processes using novel on-line techniques
… and biomass. These experiments found the Bragg wavelength shift increased as the concentration of the analytes increased for example the wavelength shift of 2.5 g/L was measured as 5.50 pm and of 15 g/L was measured as 73.41 pm. When the probe was used to analyse the fermentation samples …
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Composite Films for Modifying Evanescent Wave Characteristics in Long-Period Grating Biosensors
… the fiber holder with an accompanying peak wavelength shift that averaged 2 nm on an Optical Spectrum Analyzer with a noise level of 0.1 nm. The BSA affinity film was regenerated 50 times and showed a baseline shift of -1.3 nm.
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Resonant Detection of Nano to Microscopic Objects Using Whispering Gallery Modes
… from the microsphere surface the distance of a wavelength into the surrounding medium. This thesis demonstrates how label-free molecules binding to the microsphere surface perturb the optical resonance by interaction with this evanescent field. The effect is demonstrated by surface adsorption of …
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Band edge lasing in chiral nematic liquid crystals
… laser displays, and environmental sensing. The wavelength of emission from dye-doped chiral nematic liquid crystals is highly flexible, with lasers demonstrated across the visible range and near infra-red.This thesis investigates two routes for improving the functionality of chiral nematic …
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Ionic Self-Assembled Multilayers Adsorbed on Long Period Fiber Gratings for Use as Biosensors
… LPG, we find theoretically that the resonant wavelength shift of the LPG can result from either the variation of the thickness of the film and/or the variation of its refractive index. Furthermore, results illustrate that the sensitivity of the sensor could be enhanced using a nm-thick …
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Thermal and Optical Simulations of Vertical Cavity Surface Emitting Lasers
… has been shown to compute accurate resonant wavelength, mode profile, and threshold loss as compared to the vector Green's function method and experimental results. The vector model is based on rigorous mode matching and has been formulated to be efficient both in computation volume and …
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Fiber-Optic Sensors for Fully-Distributed Physical, Chemical and Biological Measurement
… optical transmission spectrum of the T-LPG may shift. Therefore, by measuring the T-LPG resonance wavelength at different locations along the fiber, distributed measurement can be realized for a number of parameters beyond temperature and strain. Based on this platform, fully-distributed …
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Long period fibre grating as gas sensor for environmental pollution monitoring.
… showed some optical sensitivity at the optimum wavelengths used in optical fibres to the various gases being monitored, in most cases causing a detectable change in the optical characteristics of the modes in the LPG.This study has shown the possibility of using a suitably prepared LPG as a gas …
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Novel Optical Materials for Passive Photonic Applications
… of the sol-gel and its effect on thermal wavelength shift of the microring resonance. With this method, I was able to achieve a thermal shift down to -6.8 pm/°C for transverse electric (TE) polarization, as well as thermal shifts below 1 pm/°C for transverse magnetic (TM) polarization in …
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Gamma irradiation response of photonic crystal and standard optical fibre Bragg grating sensors for radiation dosimetry
… a PCF. Previous research has indicated the Bragg wavelength shift (BWS) of standard FBGs increases with accumulated Gamma dose. This shift appears to be permanent, indicating that gamma irradiation permanently affects the Bragg wavelength of the FBG. To better understand these effects, and …
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Development and implementation of nanoscale materials in engineering applications
… Dots observed had Gaussian fitted emission peak shifts when exposed to a 5mW 405nm laser and pressures ranging from 0-100MPa. The emission peak shifts experienced appeared near linear over the ranges of 5-100MPa with an average wavelength shift of -1.5nm per 100MPa. The Quantum Dot emission peak …
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