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 33 for “"wavelength dependence"”.
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Wavelength dependence of the polarization of light reflected from a particulate surface in the spectral region of a transition metal absorption band,
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Science, 1972.
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Wavelength dependence of the spectral linewidth of a grating-tuned CW single-frequency external-cavity strained quantum well InGaAs/AlGaAs Grinsch diode laser
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 1994.
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Novel microbend loss fiber optic hydrophones for direction sensing
… on the results, an improved design that uses the wavelength dependence of microbend loss in a single mode fiber is proposed.
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Transport properties of electrons in potassium bromide
… in the temperature range of 4.2 K to 78 K. The wavelength dependence o£ the photocurrent was determined in the same range of temperature. The symmetry of the conduction band at 4.2 o K was determined from observation of the transverse magnetoconductivity. A new technique of observing cyclotron …
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Particle formation in ambient mass spectrometry
… Particle size measurements were made at IR laser wavelengths between 2.8 and 3.0 μm. The laser fluence and wavelength dependence of particle sizes from IR irradiation of glycerol and three solid matrices were investigated. The distribution of particles was characterized by a large concentration of …
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Investigation of the Chemical and Physical Properties of Asian Dust and Asian Pollution Transpacific Transport During the Intex-B Field Campaign
… dust/pollution plume boundary. The magnitude of wavelength dependence of the aerosol scattering ratios at 450, 550 and 700 nm as measured by the nephelometer demonstrates whether the plume contains fine mode aerosols; which is believed to be an excellent indicator of whether the Asian dust plume …
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Hybrid laser with CMOS photonics
… allowing for lasing at virtually arbitrary wavelengths, the possibility of multiwavelength operation with a shared gain medium, elimination of closed-loop control of wavelength tuning, ability to control laser output and wavelength on-chip, and the potential for wavelength modulation using …
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Optical studies of super-collimation in photonic crystals
… the fabrication of photonic crystals for optical wavelengths. These periodic structures of alternating high-to-low index of refraction materials allow the observation of peculiar effects, in particular, the propagation of optical beams without spatial spreading. This effect, called …
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Wavelength compensation in fused fiber couplers
The performance of fused fiber couplers is wavelength dependent. Wavelength spectral compensation is a technique to decrease the effect of the wavelength dependence, which is an essential task for many applications in fiber optic communication systems. Fiber devices such as wavelength-flattened …
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Loss phenomena in perturbed single-mode optical fibers: investigation and applications
… single-mode fibers were found to be strongly wavelength dependent. This wavelength dependence was characterized by narrow attenuation bands in the transmission spectra of periodically deformed fibers. The attenuation bands were shown to shift as the spatial deformation period was varied. The …
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Non-Thermal Contribution to Ruthenium Photothermal Catalyst in Carbon Dioxide Methanation
… cutoff near 500 nm, disappearing at longer wavelengths. This wavelength dependence suggests a non-thermal mechanism beyond simple heating. By integrating precise temperature monitoring, studying dependence on photon energy and intensities with and without external heating, this work …
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A STUDY OF CERTAIN ELECTROMAGNETIC INTERACTIONS AMONG HIGH OPTICAL CONDUCTIVITY NANOSPHERES AND DIELECTRIC HALF-SPACES
… found that the radiated power had a very strong dependence on the distance between the sphere and the substrate as well as the polarization and the angle of the incident plane wave. The wavelength dependence was also found to change significantly allowing access to regions of relatively larger …
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Laser-based optical activity detector for high performance liquid chromatography
… the sign of the optical rotation, as well as the wavelength dependence of the rotation, to aid in the identification of peaks. The working system is based on the use of a laser and high quality optics. A detection limit approaching that of the conventional UV absorption detector can be achieved in …
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Temperature-Dependent High-Speed Modulation and Wavelength Conversion Using Quantum-Well Lasers
… determine the high-speed modulation response and wavelength conversion in long-wavelength semiconductor lasers is presented. The steady-state measurement of gain is presented through four different approaches, including the direct (Hakki-Paoli) measurement of polarization-resolved spectra, …
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Characterisation of Microphysical and Optical Properties of Atmospheric Aerosols in a High Arctic environment: Villum Research Station, NE Greenland
… which control their interaction with visible wavelength radiation. This thesis focuses on the characterisation of the aforementioned aerosol properties in a High Arctic environment, Villum Research Station (Northeast Greenland), during two six-month observation periods in 2020 and 2021. The …
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Direct UV-written waveguide devices
… X-couplers that exhibit low polarisation and wavelength dependence. Maximum and minimum coupling ratios of 95% (±0.8%) and 1.9% (±1%) respectively with typical excess loss of 1.0dB (±0.5dB) were recorded. Device modelling using Beam Propagation Method (BPM) and an analytical model showed good …
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On the nature of SERS from plasmonic nanostructures
… SERS markers. Tuning of the Raman excitation wavelength allows comparison between resonance and nonresonance QD SERS and identifies enhancement due to the plasmonic nanostructure. A gentle mechano-chemical process (carbon dioxide snow jet) is used to rearrange adsorbed organic thiol monolayers …
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Bridging the Modeling-Sampling Gap for Mid-Infrared Reflectance Spectroscopy of Small Particles, Films, and Fibers
… absorption has a non-linear, stair-step-like dependence on particle coverage and a wavelength dependence that can be explained by electric field standing waves (EFSW) caused by the mirrored substrate.</p> <p>The same effect is found to cause progressive weakening of the observed intensity as a …
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Scale closure in upper ocean optical properties : from single particles to ocean color
… and non-phytoplankton bb. A higher inverse wavelength dependence of non-phytoplankton bb in the summer was caused by the contribution of small detritus, in contrast to larger minerals in the spring. Measurements of bb and Rrs were compared to values from bio-optical models based on …
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Direct Aerosol Radiative Forcing Based on Optical Measurements at Contrasting, Climatically Important Sites
… (sigma sp and sigmabsp, respectively) and their dependence upon controlled relative humidity (RH), particle diameter ( Dp) size cut, and wavelength of light were measured using a controlled RH nephelometer system. Results from Cape Grim demonstrated the predominate influence of sea-salt aerosol …
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