Diffraction efficiency

About: Diffraction efficiency is a research topic. Over the lifetime, 10320 publications have been published within this topic receiving 158298 citations.

Volume phase holographic gratings: large size and high diffraction efficiency

Abstract: Volume phase holographic gratings (VPHGs) possess unique properties that make them attractive for numerous applications. After reviewing major VPHG characteristics through theory, we discuss some aspects of the dichromated gelatin recording material and the holo- graphic recording process. The large-scale VPHG research facility set up at the Center Spatial de Liege enables production of VPHGs up to 380 mm in diameter, with fringe frequencies from 315 to 3300 lp/mm. We describe the work that has been undertaken in our laboratory to remove the last limitations inherent in VPHGs. © 2004 Society of Photo-Optical Instru- mentation Engineers. (DOI: 10.1117/1.1803557)

Volume-chirped Bragg gratings: monolithic components for stretching and compression of ultrashort laser pulses

Abstract: An innovative type of optical component—a volume Bragg grating—has recently become available commercially and has found wide applications in optics and photonics due to its unusually fine spectral and angular filtering capability. Reflecting volume Bragg gratings, with the grating period gradually changing along the beam propagation direction (chirped Bragg gratings—CBGs) provide stretching and recompression of ultrashort laser pulses. CBGs, being monolithic, are robust devices that have a footprint three orders of mag- nitude smaller than that of a conventional Treacy compressor. CBGs recorded in photo-thermo-refractive glass can be used in the spectral range from 0.8 to 2.5 μm with the diffraction efficiency exceeding 90%, and provide stretching up to 1 ns and compression down to 200 fs for pulses with energies and average powers exceeding 1 mJ and 250 W, respectively, while keeping the recompressed beam quality M 2 < 1.4, and possibly as low as 1.1. This paper discusses fundamentals of stretching and compression by CBGs, the main parameters of the gratings including the CBG effects on the laser beam quality, and currently achievable CBG specifications. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part

Volume phase gratings for spectroscopy, ultrafast laser compressors, and wavelength division multiplexing

Abstract: Volume phase (VP) gratings are now available and being applied to the applications of astronomical spectroscopy, Raman spectroscopy, ultrafast lasers, and wavelength division multiplexers. A volume phase grating results from the recording of an interferometric pattern within the volume of a material which, when suitably processed, becomes a modulation of the material's index of refraction. When a VP grating is substantially illuminated, the light interacts with the material due tot he recorded pattern. Light propagates within and out of the VP grating according to Bragg diffraction. Definitions of various VP gratings designed and fabricated to study performance are provided as relating to the applications listed above. Performance parameters include diffraction efficiency, spectral coverage, and angular coverage. Descriptions of the test methods are given. Performance data is provided and compared to the respective design.

Unidirectional excitation of surface plasmons by slanted gratings.

Abstract: Surface plasmon excitation by normally incident light on surface-relief metallic diffraction gratings is studied numerically. Predominantly unidirectional excitation is achieved with a grating of either a slanted lamellar or an inclined sinusoidal groove profile, both having shallow depths. Maps of Poynting vector illustrate that the energy flow turns from normal incidence in the far-field region to a pattern almost parallel to the grating surface in the required direction of excitation of a single SPP wave.