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.
Results
Showing 1 to 20 of 53 for “"diffraction grating"”.
-
Voltage programmable diffraction grating device
… of oil. This wrinkle is used as a variable diffraction grating that changes the wrinkle amplitude in proportion to the applied voltage squared. The device consists of a thin layer (between 8 μm and 50 μm) of 1-Decanol oil which coats a 0.5 μm thick layer of dielectric (SU8 photoresist) that …
-
Sunlight and the use of holographic diffraction grating : an environmental perspective
… fountain installation, incorporated holographic diffraction grating to diffract and focus sunlight as an environmental installation which distinguished the sun's temporal progression with color variations throughout the day. Holographic diffraction grating is a material with the potential to …
-
Intensity measurements in the arc spectrum of copper using the diffraction grating
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, 1937
-
Enhancement of Light Absorption Efficiency of Solar Cell Using Dual
… research we study the effect of adding a single diffraction grating on top of a solar cell. We simulated the square diffraction grating, as well as triangular diffraction grating. The single square grating showed more favorable results, achieved 330% power improvement compared to 270% power …
-
Investigation of porous alumina as a self-assembled diffractive element to facilitate light trapping in thin film silicon solar cells
… a backside distributed Bragg reflector with a diffraction grating for large-angle diffraction. This study develops a simple and cost-effective fabrication method of using porous alumina as a self-assembled textured photonic crystal. Porous alumina is an attractive material because under certain …
-
Development of Novel Compact Laser Sources for Bio-Medical Applications
… involved a comparison between 1st-order diffraction grating and 2nd-order diffraction grating for this tunable QD-MOPA. The result found was the maximum fundamental mode-locking (FML) wavelength tuning range. Nearly 100 nm (from 1187nm to 1283nm) wavelength tuning range was achieved under …
-
An investigation of phase-mask diffraction patterns and fibre Bragg gratings with scanning near-field optical microscopy
… optical and structural properties of fibre Bragg gratings, which are used throughout the optical fibre telecommunications network. By imaging the evanescent fields of Bragg gratings, a characterization technique has been developed which has enabled the acquisition of sub-wavelength information …
-
Investigating the operating mechanism of a diffraction based biosensor
… determining the mechanism of signal change for a diffraction-based sensor (DBS) system. The DBS detects analyte-binding events by monitoring the change in diffraction efficiency that takes place when analyte molecules adsorb to target molecules that have been patterned onto a surface. The exact …
-
Technological assessment of light-trapping technology for thin-film Si solar cell
… of Distributed Bragg Reflector (DBR) with Diffraction Grating (DG) and Anti-Reflection Coating (ARC) for thin film Si solar cell was analyzed from the technology, market, and implementation perspectives. Two applications were investigated. For monocrystalline thin film Si solar cell, layer …
-
Calibration of a microvision system for MEMS device characterization
… electrically programmable, surface micromachined diffraction grating. A microvision system has been developed to measure the electromechanical behavior of the polysilicon beams that comprise this device. Proper rigor demands that the system for making characterizations should itself be …
-
Measurements of Surface Displacements During Stress Wave Propagation in Opaque Solids Using Pulsed Laser Speckle Photography
… final specklegram is processed and treated as a diffraction grating to yield both full-field or point-by-point data concerning object displacements. The advantages of such a system include variable sensitivity recordings, non-contacting, ultra fast and it fills the gap between other experimental …
-
Alignment and actuation of compliant nanostructures and diffractive optics by inter-nanomagnet forces
… nanostructured freestanding beams such as in a diffraction grating. This actuation combines the advantages of both analog and digital tuning techniques. For both applications, theoretical work, simulations, fabrication and experimental results demonstrating the promising power of nanomagnets …
-
Development of small-diameter endoscope capable of high-resolution visualization and laser therapy through a shared optical aperture
… (SEE), which uses an optical chain with a diffraction grating at the distal end to spectrally encode the (broadband) optical illumination signal in a line across the surgical scene.
-
Applications of a fast helmholtz solver in exploration seismology
… in the horizontal direction, much like a diffraction grating. This Helmholtz solver achieves significant computational speed by restricting the velocity model to consists of a number of non-overlapping piecewise layers.
-
Paviršinių difrakcinių elementų optimizavimas ir formavimas femtosekundiniais UV lazerio impulsais /
… devices in modern science and technology is the diffraction grating. Traditional methods of manufacturing diffraction gratings, such as etching, lithography, and others, face various challenges, including limited design capabilities and high costs. With the advancement of laser technologies and …
-
Optical properties of III-V semiconductors
… exciting one mode at a time using a real-space diffraction grating coupler. The resulting eigenmode distributions were used to obtain the refractive index of GaAs at a matrix of sub bandgap photon energies (1.40 eV $<$ h$\nu <$ 1.50 eV) and temperatures (40 K $<$ T $<$ 300 K). Values for the …
-
Characterisation of grating properties for MOTs at multiple wavelengths and laser cooling Rb on the 5S1/2 - 6P3/2 transition at 420nm
… trap (MOT) utilizing a reflective diffraction grating, a 780nm and a 420nm laser. Taking advantage of the narrower line width of the 6P3/2 state, 420nm lasers can theoretically make a factor of 10 colder MOT than those using 780nm ones based on the Doppler limit. However, …
-
Theory, Design, and Fabrication of Diffractive Grating Coupler for Slab Waveguide
… theory design and fabrication of a diffractive grating coupler. The first part of the design process is to choose the period of the grating coupler based on the desired coupling angle. The second part of the design process is to choose the geometry of the grating that gives maximum coupling …
-
The effect of internal waves on long range acoustic propagation in the ocean
… is found that the internal wave field acts as a diffraction grating in permtting only certain scattered acoustic waves to propagate through the waveguide. Since the internal waves are continuously distributed in wavenumer space, the acoustic fluctuations become a statistical average with a bias …
Page 1 of 3