Transmission and laser damage studies of fused silica and PMMA debris shields with picosecond light pulses

Abstract

Progress in building high-energy, short pulse laser systems with peak powers in the 100 to 1000 TW regime and applying them to plasma physics experiments has highlighted the need for debris mitigation solutions compatible with high intensity pulses [1]. Mitigation schemes ideally need to protect focusing optics for a number of laser pulses at reasonable cost without degrading beam quality. In this paper we describe preliminary experiments performed at the VULCAN laser facility to address some of these issues. The short pulse beam was passed through a thin optical shield at intensities up to 4 x 1012 W/cm2. The transmission of the shield was measured as a function of intensity along with the near and far field beam quality. Transmission losses occurred at the highest intensities used and these were related to the start of laser damage of the shield. The morphology of the damage features on the surface and in the bulk material was studied by a combination of white light interferometry as well as optical and scanning electron microscopy.