title: Improvement and formation of UV-induced damage on LBO crystal surface during long-term high-power third-harmonic generation.
abstract: We demonstrate the improvement and formation of UV-induced damage on LBO crystal output surface during long-term (130 h) high-power (20 W) high-repetition-rate (80 kHz) third-harmonic generation. The output surface was super-polished (RMS surface roughness <0.6 nm) to sub-nanometer scale super smooth roughness. The surface lifetime has been improved more than 20-fold compared with the as-polished ones (RMS surface roughness 4.0~8.0 nm). The damage could be attributed to the consequence of thermal effects resulted from impurity absorptions. Simultaneously, it was verified that the impurities originated in part from the UV-induced deposition.
authors.affiliation: State Key Laboratory of Tribology, Center for Photonics and Electronics, Department of Precision Instruments, Tsinghua University, Beijing 100084, China.
authors.forename: Hailong
authors.initials: H
authors.lastname: Hong
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.forename: Mali
authors.initials: M
authors.lastname: Gong
mesh_terms: D001881:Borates / Q000737:chemistry* / Q000528:radiation effects*; D018020:Lithium Compounds / Q000737:chemistry* / Q000528:radiation effects*; D008422:Materials Testing; D013499:Surface Properties / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D001881:Borates; D018020:Lithium Compounds; C021051:lithium borate