Scanning electron microscope study of laser-damaged beryllium thin films

Abstract

Laser damage in Be films vacuum vapor deposited onto polished glass substrates was investigated in the scanning electron microscope. Surface scratches were observed to raise thermal gradients and promote premature melting and film degradation in Be films 0.1–0.3 μ thick for beam intensities of 40–55 MW. The damage zones were characterized by radially symmetric melting and evaporation consistent with a cross-sectional distribution of laser-beam energy. The results indicate that vaporization contributes prominently to Be film degradation by laser-beam irradiation.