Comparison of laser-induced damage in Ta_2O_5 and Nb_2O_5 single-layer films and high reflectors  

作　　者：许程 赵宇龙 强颖怀 朱亚波 郭立童 邵建达 

机构地区：[1]School of Materials Science and Engineering,China University of Mining and Technology [2]Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences

出　　处：《Chinese Optics Letters》2011年第1期90-93,共4页中国光学快报（英文版）

基　　金：supported by the Fundamental Research Funds for the Central Universities under Grant No.2009A058

摘　　要：Ta2O5 and Nb2O5 films are deposited on BK7 glass substrates using an electron beam evaporation method and are annealed at 673 K in the air. In this letter, comparative studies of the optical transmittance, microstructure, chemical composition, optical absorption, and laser-induced damage threshold （LIDT） of the two films are conducted. Findings indicate that the substoichiometric defect is very harmful to the laser damage resistance of Ta2O5 and Nb2O5 films. The decrease of absorption improves the LIDT in films deposited by the same material. However, although the absorption of the Ta2O5 single layer is less than that of the Nb2O5 single layer, the LIDT of the former is lower than that of the latter. High-reflective （HR） coatings have a higher LIDT than single layers due to the thermal dissipation of the SiO2 layers and the decreased electric field intensity （EFI）. In addition, the Nb2O5 HR coating achieves the highest LIDT at 25.6 J/cm^2 in both single layers and HR coatings.Ta2O5 and Nb2O5 films are deposited on BK7 glass substrates using an electron beam evaporation method and are annealed at 673 K in the air. In this letter, comparative studies of the optical transmittance, microstructure, chemical composition, optical absorption, and laser-induced damage threshold （LIDT） of the two films are conducted. Findings indicate that the substoichiometric defect is very harmful to the laser damage resistance of Ta2O5 and Nb2O5 films. The decrease of absorption improves the LIDT in films deposited by the same material. However, although the absorption of the Ta2O5 single layer is less than that of the Nb2O5 single layer, the LIDT of the former is lower than that of the latter. High-reflective （HR） coatings have a higher LIDT than single layers due to the thermal dissipation of the SiO2 layers and the decreased electric field intensity （EFI）. In addition, the Nb2O5 HR coating achieves the highest LIDT at 25.6 J/cm^2 in both single layers and HR coatings.

关 键 词：ABSORPTION Electric fields Electron beams Laser damage Reflective coatings Silicon compounds SUBSTRATES TANTALUM 

分 类 号：O484.41[理学—固体物理]