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Morphology and growth properties of nano- and submicrometer-scale initial damage sites under 355  nm wavelength pulsed laser irradiation.

The initial damage of optical elements under irradiation of a 355 nm wavelength nano-second pulsed laser below the laser-induced damage threshold mainly includes nano- and submicrometer-scale craters. The morphology and growth characteristics of such small-scale damage, which are different from those of larger-scale damage, have not been fully clarified. In this study, laser-induced nano- and submicrometer-scale initial damage of fused silica was investigated by atomic force microscope. The morphology of craters and ejecta was analyzed, and the relationship between the structure characteristics and the irradiation parameters was obtained. In addition, the growth and evolution features under multipulsed laser irradiation were classified.