FEMTOSECOND TRANSIENT REFLECTION FROM POLYMER SURFACES DURING FEMTOSECOND UV PHOTOABLATION

A subpicosecond KrF laser system (248 nm, 0.5 ps) was used as a light source for ablation of PMMA Mylar and Kapton. The time-dependent refle ctivity of the light-induced plasma mirror as measured by 496 nm, 0.5 ps long probe pulses showed an increase of up to 94% with 0.4-1 ps ris e time and 10-15 ps fall time. The high-density plasma mirror shows pe rfect optical quality, and seems to be a promising light-controlled ul trafast switch for UV and visible light. The spectrum of the UV light reflected from the ablated spot is blue shifted by 0.5 nm and shows 1 nm broadening.