Topic
Diffraction efficiency
About: Diffraction efficiency is a research topic. Over the lifetime, 10320 publications have been published within this topic receiving 158298 citations.
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TL;DR: It is shown that the intensity in a grating's near field can be enhanced significantly compared with conventional interferometric lithography, and predicted that high-intensity, high-contrast patterns with 135-nm period can be formed in photoresists more than 50 nm thick.
Abstract: Simulation results are presented to illustrate the main features of what we believe is a new photolithographic technique, evanescent interferometric lithography (EIL). The technique exploits interference between resonantly enhanced, evanescently decaying diffracted orders to create a frequency-doubled intensity pattern in the near field of a metallic diffraction grating. It is shown that the intensity in a grating’s near field can be enhanced significantly compared with conventional interferometric lithography. Contrast in the interference pattern is also increased, owing to a reduction in the zeroth-order transmission near resonance. The pattern’s depth of field reduces as the wavelength is increased beyond cutoff of the first-order diffracted components, and results are presented showing the trade-offs that can be made between depth of field and intensity enhancement. Examples are given for a 270-nm-period grating embedded in material with refractive index n = 1.6 and illuminated with wavelengths near 450 nm. Under these conditions it is predicted that high-intensity, high-contrast patterns with 135-nm period can be formed in photoresists more than 50 nm thick.
62 citations
TL;DR: Preliminary experiments demonstrated that the devitrification could be induced photolytically with 4880-A light and that holograms could be formed in these materials.
Abstract: Although glass formation in the arsenic-sulfur system was reported as early as 1870 it is only since the early 1950's that any considerable attention has been given to such vitreous systems. Since then numerous papers have appeared dealing with arsenicsulfur glasses and with glasses derived from this system by addition and substitution of various elements. The field has been reviewed by Pearson. Most of the earlier studies have been concerned with the glassforming tendencies of various systems and with the physical, chemical, optical, electrical, and photoelectric properties of the resulting glasses. However, to the best of our knowledge no publications concerning the photochemical properties of these systems have appeared to date. I t is well known that binary arsenic-sulfur glasses and ternary arsenic-sulfur-bromine glasses with very high sulfur contents will devitrify spontaneously, precipitating elemental sulfur.Since all of these materials absorb energy very strongly in the visible region, it was of interest to ascertain whether light would induce the devitrification process in an otherwise stable glass. If such a change could be brought about, then the refractive index changes associated with the devitrification could be applied to hologram formation. Preliminary experiments demonstrated that the devitrification could be induced photolytically with 4880-A light and that holograms could be formed in these materials.
62 citations
TL;DR: Nanoparticles are spatially arranged by holographical means in a photopolymer that show remarkably efficient diffraction of cold neutrons up to about 50% for effective thicknesses of only 200 μm, which opens up a profound perspective for next generation neutron-optical devices with the capability to tune or modulate the neutron diffraction efficiency.
Abstract: We report a breakthrough in the search for versatile diffractive elements for cold neutrons Nanoparticles are spatially arranged by holographical means in a photopolymer These grating structures show remarkably efficient diffraction of cold neutrons up to about 50% for effective thicknesses of only $200\text{ }\ensuremath{\mu}\mathrm{m}$ They open up a profound perspective for next generation neutron-optical devices with the capability to tune or modulate the neutron diffraction efficiency
62 citations
TL;DR: The optothermal expansion coefficient is used to design athermalized lenses that combine refractive and diffractive surfaces and useful design equations are presented that describe focal length, phase coefficients, and diffraction efficiency as functions of temperature.
Abstract: The thermal properties of lenses play an important role in the performance of optical systems. We discuss the effects of uniform temperature changes and thermal gradients on diffractive lens performance. Comparisons are made between the thermal sensitivity of refractive and diffractive lenses. Useful design equations are presented that describe focal length, phase coefficients, and diffraction efficiency as functions of temperature. We present important thermal data for a number of lens materials. The optothermal expansion coefficient is used to design athermalized lenses that combine refractive and diffractive surfaces.
62 citations
IBM1
TL;DR: Photographic processing techniques for producing high efficiency, low noise phase holograms on silver halide emulsions have been investigated and holograms obtained which yield approximately 30% diffraction efficiency and signal to scattered noise in excess of 50:1 in the reconstruction of a diffuse wave-front.
Abstract: Photographic processing techniques for producing high efficiency, low noise phase holograms on silver halide emulsions have been investigated. Control of the emulsion and maintenance of the integrity of the holographic record throughout all processing were identified as prime requisites for high quality holographic reconstructions. Holograms have been obtained which yield approximately 30% diffraction efficiency and signal to scattered noise (S/N) in excess of 50:1 in the reconstruction of a diffuse wavefront. Holographic interferometry and ghost imaging with diffuse subjects has also been achieved with these techniques.
61 citations