Influence of Different Substrates on Laser Induced Damage Thresholds at 1064nm of Ta2O5 Films

Ta₂O₅ films are prepared on Si, BK7, fused silica, antireflection (AR) and high reflector (HR) substrates by electron beam evaporation method, respectively. Both the optical property and laser induced damage thresholds (LIDTs) at 1064nm of Ta₂O₅ films on different substrates are investigated before and after annealing at 673K for 12h. It is shown that annealing increases therefractive index and decreases the extinction index, and improves the O/Ta ratio of the Ta₂O₅ films from 2.42 to 2.50. Moreover, the results show that the LIDTs of the Ta₂O₅ films are mainly correlated with three parameters: substrate property, substoichiometry defect in the films and impurity defect at the interface between the substrate and the films. Details of the laser induced damage models in different cases are discusse .