title: Pulse compression grating fabrication by diffractive proximity photolithography.
abstract: We report about a newly devised throughput-scalable fabrication method for high-quality periodic submicron structures. The process is demonstrated for optical transmission gratings in fused silica with a period of 800 nm (1250  lines/mm) to be used in laser pulse compression. The technology is based on an innovative advancement of i-line proximity photolithography performed in a mask aligner. The aerial image is encoded in a rigorously optimized electron-beam-written three-level phase mask which is illuminated by an adapted multipole configuration of incidence angles. In comparison to conventional proximity lithography, the process enables a significantly higher resolution while maintaining a good depth of focus--in contrast to lithography based on direct Talbot-imaging. Details about the grating fabrication process and characterization of fabricated pulse compression grating wafers are presented. The gratings show a diffraction efficiency of 97% at a wavelength of 1030 nm and a wavefront error comparable to gratings fabricated by electron-beam lithography.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Stuerzebecher
authors.forename: Frank
authors.initials: F
authors.lastname: Fuchs
authors.forename: Torsten
authors.initials: T
authors.lastname: Harzendorf
authors.forename: Uwe D
authors.initials: UD
authors.lastname: Zeitner