High-efficiency dielectric reflection gratings: design, fabrication, and analysis

Abstract

We report on reflection gratings produced entirely of dielectric materials. This gives the opportunity to enhance the laser damage threshold over that occurring in conventional metal gratings used for chirped-pulse-amplification, high-power lasers. The design of the system combines a dielectric mirror and a well-defined corrugated top layer to obtain optimum results. The rules that have to be considered for the design optimization are described. We optimized the parameters of a dielectric grating with a binary structure and theoretically obtained 100% reflectivity for the -1 order in the Littrow mounting for a 45 degrees angle of incidence. Subsequently we fabricated gratings by structuring a low-refractive-index top layer of a multilayer stack with electron-beam lithography. The multilayer system was fabricated by conventional sputtering techniques onto a flat fused-silica substrate. The parameters of the device were measured and controlled by light scatterometer equipment. We measured 97% diffraction efficiency in the -1 order and damage thresholds of 4.4 and 0.18 J/cm(2) with 5-ns and 1-ps laser pulses, respectively, at a wavelength of 532 nm in working conditions.

High-efficiency wide-band metal-dielectric resonant grating for 20 fs pulse compression

“…Originally it was suggested to use an alldielectric structure composed of a multilayer mirror with a dielectric corrugation on top [4] as an alternative. This motivated further developments [5,6] which, in the midnineties, led to the demonstration of large dielectric gratings at 1050 nm wavelength capable of withstanding significantly higher flux [7]. Since around 2000 the company Jobin & Yvon have also developed commercial elements [8].…”

Optical characterization of ultrahigh diffraction efficiency gratings

“…Dielectric reflection gratings with diffraction efficiencies of 96%, 97%, and 99% have been reported. [3][4][5] However, the measurement techniques used in those applications allowed for only a rough estimation of the diffraction efficiency, and no error bars for the values were given. Diffraction gratings may also be used in advanced high-power laser interferometers, 6,7 where they allow for the all-reflective realization of beam splitters and cavity couplers, and therefore may help reduce thermal effects in the substrate, such as thermal lensing 8 and thermorefractive noise.…”

Design and Fabrication of High-Performance Liquid Crystal Gratings

“…As the simplest form of the BOE, several binary gratings with onedimensional periodicity have been theoretically studied [8], and fabricated to achieve high diffraction efficiency [8,9]. In general, the BOEs were fabricated by utilizing complicated micro-lithographic techniques [10,11] or multi-layered dielectric coatings [12] in recent years.…”