Investigation of the initial stage of laser damage to glass by optical and microwave methods

An experimental investigation was made of luminescence and microwave absorption in the region of interaction of λ= 1.06-μ laser radiation, of 10-msec pulse duration, with an optical glass surface. It was found that prior to the onset of intense evaporation and the formation of an erosion jet, a gas bubble formed near the glass surface, its appearance and development being accompanied by intense luminescence with a continuous spectrum. When the bubble disintegrated, gas was ejected into the atmosphere and there was a sharp drop in the luminescence intensity. The electron densities in the gas stream and the erosion jet were measured and the effective brightness and color temperatures of the gas in the bubbles were determined.