Influence of SiO 2 additional layers on the laser induced damage threshold of Ta 2O 5 films

Abstract

A series of Ta 2O 5 films with different SiO 2 additional layers including overcoat, undercoat and interlayer was prepared by electron beam evaporation under the same deposition process. Absorption of samples was measured using the surface thermal lensing (STL) technique. The electric field distributions of the samples were theoretical predicted using thin film design software (TFCalc). The laser induced damage threshold (LIDT) was assessed using an Nd:YAG laser operating at 1064 nm with a pulse length of 12 ns. It was found that SiO 2 additional layers resulted in a slight increase of the absorption, whereas they exerted little influence on the microdefects. The electric field distribution among the samples was unchanged by adding an SiO 2 overcoat and undercoat, yet was changed by adding an interlayer. SiO 2 undercoat. The interlayer improved the LIDT greatly, whereas the SiO 2 overcoat had little effect on the LIDT.