Large Area High Efficiency Broad Bandwidth 800 nm Dielectric Gratings for High Energy Laser Pulse Compression

Abstract

We have demonstrated broad bandwidth large area (229 mm x 114 mm) multilayer dielectric diffraction gratings for the efficient compression of high energy 800 nm laser pulses at high average power. The gratings are etched in the top layers of an aperiodic (Nb 0.5 Ta 0.5) 2 O 5-SiO 2 multilayer coating deposited by ion beam sputtering. The mean efficiency of the grating across the area is better than 97% at the center wavelength and remains above 96% at wavelengths between 820 nm and 780 nm. The gratings were used to compress 5.5 J pulses from a Ti:sapphire laser with an efficiency above 80 percent.

Design of high-efficiency ultrabroadband dielectric gratings

“…This optimization procedure has led to higher than 97% DE in the -1st order over a 110 nm wavelength range at around 800 nm without decrease of the DE in the bandgap. Dielectric gratings for high-power laser pulse compression is already demonstrated at around the 800 nm central wavelength [12]. That grating used alternating high Nb 0.5 Ta 0.5 2 O 5 and low SiO 2 layers having high enough index contrast to obtain a 40 nm bandwidth with larger than 96% efficiency.…”

Influence of horizontal damage size of grating ridge on the optical properties of multilayer dielectric gratings

“…The fabricated broadband MDG has realized 40 nm bandwidth with more than 96% reflective diffraction efficiency [9]. According to research into laserinduced damage characteristics of MDGs, internal electric field enhancement in the grating ridge is critical for laser damage resistance of MDGs in high-energy laser systems [10][11][12].…”

Design of high-efficiency broad-bandwidth pulse compression device based on composite transmission grating with high damage threshold

“…To obtain higher energy output and meanwhile to avoid induced damage of grating under the high-power laser, the larger scale of the grating is better. While the magnification in scale will augment the difficulty of fabrication grating [2] .…”