Excimer laser interaction with dielectric thin films

摘要

Utilizing thermal Mirage technique, UV laser damage resistivity studies on electron beam evaporated LaF_3/MgF_2 and Al_2O_3/SiO_2 reflecting multilayer stacks have been performed at lambda=248 nm, tau=20 ns. Investigating these stacks by changing the number of (H,L) pairs, different coating properties were shown to be responsible to UV single-shot laser damage. The high damage resistivity of the Al_2O_3/SiO_2 multilayers is caused by low defect density, whereas the damage of LaF_3/MgF_2 stacks origins from defects which are incorporated in the layers during the deposition process.