<title>Diffraction gratings for lasers with pulse compression: comparative research</title>

Abstract

Diffraction gratings are key elements of laser systems with pulse compression. For providing of high peak power subpicosecond pulses these gratings should have a high damage threshold, large aperture and high optical quality. In the present work comparison holographic and ruled gratings for systems ofpulse compression is spent. Ruled gratings had spatial frequency 1740 grooves/mm, and holographic -1700 grooves/mm and were covered by gold, that provided 90 % diffraction efficiency to the first diffraction order. Measurements of damage thresholds for 1 ps and 0.5ns pulses have shown that for ruled grating it more than for holographic. It was probably connected to a thicker layer of metal for ruled gratings. To increase of a grating's damage threshold additional multi layer dielectric coatings were used. Computer calculations have shown that by changing of amount, material and thickness of layers it is possible to significantly improve damage thresholds. Experimental measurements have shown that for four layers there is the increase ofthresholds in 2 times. Received thresholds show, that for the being available sizes as ruled (l7Oxl7O mm), and holographic (200x400 mm) gratings generation of multyterrawatt laser pulses in CPA laser systems is possible.

Methods for improving ion beam etching uniformity of large-sized DOEs

“…Large-sized diffraction optics elements (DOEs) fabricated by UV lithography and ion beam etching (IBE) are important for high laser system [1][2][3][4][5][6][7] . Ion beam etching is an important kind of dry etching process, which was developed in the 1970s, and is widely used to transfer the precision patterns of micro-electronic devices.…”

Reactive ion beam etching of large-aperture multilayer diffraction gratings by radio frequency ion beam source

“…Large-aperture multilayer diffraction gratings fabricated by holographic lithography and ion beam etching are important for high-power laser system for laser pulse compression [1][2][3][4][5][6][7] . The HfO 2 and SiO 2 are two kinds of grating material commonly used in this field, which have high diffraction efficiency and high laser damage threshold [1][2][3][4] .…”