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° 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<sup>2</sup> with 5-ns and 1-ps laser pulses, respectively, at a wavelength of 532 nm in working conditions.
© 1999 Optical Society of America
(050.0050) Diffraction and gratings : Diffraction and gratings
(050.1950) Diffraction and gratings : Diffraction gratings
(320.0320) Ultrafast optics : Ultrafast optics
(320.5520) Ultrafast optics : Pulse compression
Karl Hehl, Joerg Bischoff, Ullrich Mohaupt, Martin Palme, Bernd Schnabel, Lutz Wenke, Ragnar Bödefeld, Wolfgang Theobald, Eberhard Welsch, Roland Sauerbrey, and Hartmut Heyer, "High-Efficiency Dielectric Reflection Gratings: Design, Fabrication, and Analysis," Appl. Opt. 38, 6257-6271 (1999)