| dc.description.abstract |
As the development of high power laser, optical thin films have been required to stand higher laser energy and power, and also laser induced damage threshold, especially the high reflection laser mirrors. Therefore, focus on the research of laser damage threshold (LIDT) of high reflection multilayer thin films. Using different deposition methods and materials to design the high reflection laser mirrors. High reflection laser mirrors at wavelength of 808 nm and 532 nm have been tested by 808 nm CW laser, 800 nm pulse laser and 532 nm pulse laser respectively. The damaged morphologies of the coatings have been characterized by OM and SEM, with varied laser energy and power to destroy the coatings.
The film stack of conventional design of the high reflection laser mirror is S / (HL)9 H / Air, S refers to substrate, and H, L denote Ta2O5, SiO2 layers with quarter-wavelength optical thickness (QWOT), the center wavelength is 808 nm, whose LIDT of deposited by the ion beam sputtered deposition and the electron beam evaporation with ion-beam assisted deposition can achieve 1,953 W/cm2 for nine minutes and thirteen minutes, respectively. And the film stack of conventional design was S / (HL)9 H / Air and the center wavelength is 532 nm, whose LIDT of deposited by ion bean sputtered and electron beam evaporation with ion-beam assisted deposition achieve 4.08 J/cm2 and 4.89 J/cm2 respectively. By using different deposition methods and materials to design the high reflection laser mirrors, which combining two oxide coating stacks, the structure expresses as S / (HL)9 MLM 2L / Air, and M denote Al2O3 layers with QWOT, deposited by electron beam evaporation with ion-beam assisted deposition. The LIDT of the double stack high reflection coatings increase to 7.61 J/cm2, presented a 50 % increase than the conventional high reflection coatings (4.89 J/cm2) . | en_US |