title: 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.
authors.affiliation: Ing-Büro Optimod, Ricarda-Huch-Weg 12, D-07743 Jena, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Hehl
authors.forename: J
authors.initials: J
authors.lastname: Bischoff
authors.forename: U
authors.initials: U
authors.lastname: Mohaupt
authors.forename: M
authors.initials: M
authors.lastname: Palme
authors.forename: B
authors.initials: B
authors.lastname: Schnabel
authors.forename: L
authors.initials: L
authors.lastname: Wenke
authors.forename: R
authors.initials: R
authors.lastname: Bödefeld
authors.forename: W
authors.initials: W
authors.lastname: Theobald
authors.forename: E
authors.initials: E
authors.lastname: Welsch
authors.forename: R
authors.initials: R
authors.lastname: Sauerbrey
authors.forename: H
authors.initials: H
authors.lastname: Heyer