The laser-induced damage behaviors of chirped mirrors (CMs) are studied by single 800 nm, 38 fs lasers. The CMs provide group delay dispersion of around -60fs2and average reflectivity of about 99.4% with bandwidth range of 200-300 nm at a central wavelength of 800 nm. Interestingly, a circular blister feature appears in the CMs at a wide range of laser fluence. An optical microscope, atomic force microscope, scanning electron microscope, and surface profiler are applied to describe the blister characteristics. An adiabatic expansion model of ideal gas is adopted to illustrate the formation dynamics of blisters. The evolution of blisters can be explained by partial evaporation of the film and a subsequent gas expansion, driving the bulging of the film stack up to the stress limit, where the blister fractures. According to this model, the energy absorption ratio of blisters increases monotonously with increasing laser fluence before the occurrence of the focal spot confinement effect.
Chinese Acad Sci, Xinjiang Tech Inst Phys & Chem, Key Lab Funct Mat & Devices Special Environm CAS, Urumqi 830011, Peoples R China;Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, Key Lab Mat High Power Laser, Shanghai 201800, Peoples R China;Chinese Acad Sci, Grad Univ, Beijing 100049, Peoples R China; Shandong Normal Univ, Sch Informat Sci & Engn, Shandong 250358, Peoples R China;Chinese Acad Sci, Shanghai Inst Opt & Fine Mech, State Key Lab High Field Laser Phys, Shanghai 201800, Peoples R China
Chen, Shunli,Gao, Pengpeng,Zhao, Yuanan,et al. Thermal-dynamical analysis of blister formation in chirped mirror irradiated by single femtosecond lasers[J]. Applied Optics,2014,53(15):3347-3354.