Properties and focusing conditions of laser microplasma for glass structuring

Currently, there is an increased interest among scientists in laser-induced methods (LIPAA, LIBDE, LIMP) for optical materials processing. The plume is formed due to the interaction of laser radiation transmitted through the glass sample with an absorbing target. In particular, our team is working on laser-induced microplasma (LIMP) glass processing method development, which is realized by a plasma plume action arising at the interface of a carbon-based target and an optically transparent sample. Basically, the plasma plume can be considered as a spot tool that forms micro and nano-dimensional relief on the surface of a transparent sample. This tool possesses some characteristics to be investigated: geometry, divergence, and temperature. Detailed knowledge of these characteristics will improve the processing results.

Here, we report on a detailed experimental study of glass processing by LIMP. The results are supported with calculation of a laser beam distortion by the microlens formed on the glass backside. This distortion affects on the plasma plume inducing radiation spot, and as a result, reduce the efficiency and accuracy of glass processing. The study contributes to understanding the importance of experimental conditions - air gap, focus plane position, to improve the quality of the indirect laser-plasma method.