Experimental research on thermal and dynamic effects of K9 optical lenses irradiated by low frequency femtosecond laser

Damages by a laser to materials are mainly caused by thermal and dynamic effects; such effects are referable for evaluating damage by a laser to the optical lens and the design of a laser system. We have designed several independent laser–material interaction measurement systems and carried out experimental research based on them. The results show that the laser plasma oscillation frequency is 500 Hz and accompanied by discharge phenomena. The average pressure stress on the material is 1.1 GPa; then it attenuates to the Lamb wave; and the surface coating of the lens reduces the radius of the heat-affected zone to one third of that without film.