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 found that three- element cascades can exhibit spectral and field angle bandwidths essentially as broad as two-element cascades and that these bandwidths are in excess of 2300 A and 7° respectively.
Abstract: A comprehensive treatment is presented for the diffraction efficiencies of transmission holographic elements and cascade lenses when subject to broad spectral and field angle detunings. Experimental measurements are made in support of our theory on holographic optical elements fabricated in bleached silver-halide emulsions and in dichromated gelatin. The theory of holographic grating diffraction efficiency is studied through two approaches. A numerical treatment based on the theory of thin grating decomposition is implemented and shown to be in close agreement with other theories. Additionally, a more approximate approach is pursued in which the volume grating is treated as a phased array of scatterers. The latter approach leads to closed-form formulas in addition to a simple physical picture of volume effects. It is found that three-element cascades can exhibit spectral and field angle bandwidths essentially as broad as two-element cascades and that these bandwidths are in excess of 2300 A and 7° respectively.
37 citations
TL;DR: In this paper, a hybrid aspherical diffractive lens designed to compensate for chromatic aberration was fabricated by precision glass molding and the diffractive features were integrated on the aspherial surface to avoid mold alignment during fabrication.
Abstract: The hybrid aspherical diffractive singlet achromat design can be used to reduce chromatic aberration in compact optical systems. In this paper, the development of a compression molded, low cost and high precision hybrid diffractive glass lens is described. Specifically, an aspherical diffractive lens designed to compensate for chromatic aberration was fabricated by precision glass molding. The diffractive features are integrated on the aspherical surface to avoid mold alignment during fabrication. As part of the effort to lower manufacturing cost, the diffractive profiles were directly fabricated by single-point diamond turning without polishing. A thin layer of platinum?iridium coating was applied to the mold surfaces to protect the mold inserts from degradation during the molding process. In order to reduce thermal shrinkage error, the hybrid lens was fabricated using a two-step precision molding process on a commercial glass molding machine. The geometry of the molded hybrid aspherical diffractive lens was measured using an optical profilometer and the results demonstrated a match to the design mold profile with a replication error of 0.16% in the radial direction and 6.3% in the axial direction. In addition, an optical metrology system to evaluate the diffraction efficiency and chromatic focal shift was constructed and the measured results showed that the hybrid lenses indeed function as designed.
37 citations
TL;DR: In this article, the diffraction efficiency of a phase-only spatial light modulator with a large dynamic phase range was studied. But the authors used a phase only device that reached 4 π phase modulation depth for the wavelength of 454 nm.
37 citations
TL;DR: A simple method to make a switchable liquid crystal (LC) Fresnel lens with high diffraction efficiency and a low driving voltage was proposed based on the photo-induced surface modification of the vertical alignment layer.
Abstract: A simple method to make a switchable liquid crystal (LC) Fresnel lens with high diffraction efficiency and a low driving voltage was proposed based on the photo-induced surface modification of the vertical alignment layer. UV illumination alters the pretilt angle of alignment layers, a Fresnel zone-distribution hybrid alignment in the homeotropic LC cell can be straightforwardly achieved through UV exposure, yielding a concentric structure of the Fresnel phase LC lens. A remarkable diffraction efficiency of ~31.4%, close to the measured diffraction efficiency of the used Fresnel-zone-plate mask of 32%, was detected using a linearly polarized incident beam.
37 citations
TL;DR: In this article, the diffraction efficiency curves of planar waveguides with corrugation on the waveguide-air boundary or on the substrate boundary were calculated as a function of the angle of incidence.
Abstract: The diffraction efficiency curves are calculated as a function of the angle of incidence for planar waveguides with corrugation on the waveguide-air boundary or on the waveguide-substrate boundary, respectively. It is shown that the reflectance of the system is increased up to 100% because of the excitation of the waveguide mode. A detailed phenomenological study is carried out taking into account the influence of the waveguide thickness and the corrugation depth. Possible applications of these waveguides as a narrow-band reflection filter and selective mirror are discussed.
37 citations