The Influence of Laser Plasma Effects on the Characteristics of Thin Film Damage
HAN Jing-hua1, DUAN Tao2, GAO Xu-hua3, FENG Guo-ying1*, FAN Wei-xing1，YANG Li-ming3, LIU Yan-yan1, BAO Ling-dong1
1. College of Electronics & Information Engineering, Sichuan University, Chengdu 610064, China 2. Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology, Mianyang 621010, China 3. Fine Optical Engineering Research Center, Chengdu 610041, China
Abstract：Optical components with higher surface quality and higher damage threshold requirement are necessary in high-energy/power laser system, which strongly depends on the performance of optical thin films. The damage morphologies on the surface of the HfO2/SiO2 anti-reflection film, caused by focused laser pulses, were investigated in the present paper. The studies revealed that the shock wave formed with the expansion of laser plasma, and its velocity and pressure decease rapidly with the radius. The spectrum of laser plasma, recorded by EEP2000 spectrometer, shows that the wavelength of laser plasma radiation is shorter than incident laser, which will increase the probability of multi-photon absorption; the photon energy in deep ultraviolet region, higher than the band gap of HfO2, can be absorbed directly. The ionization effect of laser plasma can easily induce film damage. The combination of shock wave and ionization effect determines the damage morphology of films. In the case of laser pulse focused on the film surface, the radiation and shock wave effects are the highest, not only the film is removed, but also the quartz substrate is broken-down. When the focus point is away from the film surface to a certain distance, the radiation of laser plasma and shock wave decrease rapidly, as a result, no damage can be found except that the thin-film can be peeled away from the substrate.
韩敬华1，段 涛2，高胥华3，冯国英1*，范卫星1，杨李茗3，刘岩岩1，包凌东1 . 激光等离子体效应对薄膜损伤特性的影响[J]. 光谱学与光谱分析, 2012, 32(05): 1162-1165.
HAN Jing-hua1, DUAN Tao2, GAO Xu-hua3, FENG Guo-ying1*, FAN Wei-xing1，YANG Li-ming3, LIU Yan-yan1, BAO Ling-dong1. The Influence of Laser Plasma Effects on the Characteristics of Thin Film Damage . SPECTROSCOPY AND SPECTRAL ANALYSIS, 2012, 32(05): 1162-1165.
