Translator Disclaimer
16 November 2018 Laser induced pits in optical coatings
Author Affiliations +
A kind of HfO2/SiO2 355nm and 1064nm high-reflective (HR) coatings were deposited by electron beam evaporation. Laser-induced damage of the coatings were tested by 355nm-7ns pulses, 355nm-1ns pulses and 1064nm-30ps pulses in 1-on-1 mode. All tests were carried out with S-polarized and P-polarized pulses in two angles of incidences (AOIs) of 30° and 50°. Damage morphologies and cross-sectional profiles were characterized using scanning electron microscope (SEM) and focused ion beam (FIB), respectively. It is shown that the typical morphologies in all the tests were μm-sized pits. In the 1064nm-30ps tests, the damage pits appeared mostly as 3-4μm ripple-like pits with a density of 13000-25000 mm-2, accompanied by a few tiny pits around. The ripple-like pits were all conical pits with a cylindrical cavity at the bottom, the depth of which was around 1μm. The tiny pits were all cylindrical shaped with a depth of about 400nm. In the 355nm-7ns tests, most of the pits were flat-pits scaled from 4 to 18μm with a density of 500-900 mm-2, few with a bulge in the bottom. The depth of the pits increased with their size, which can be 2.5μm for the largest ones. In the 355nm-1ns tests, pits appeared to be similar with those in 355nm-7ns tests, with a smaller size of 4-6 μm, The damage pits were preliminary inferred to be formed because of the material removal induced by the thermal stress.
© (2018) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yuan'an Zhao, Cheng Li, Yun Cui, Meiping Zhu, and Jianda Shao "Laser induced pits in optical coatings", Proc. SPIE 10805, Laser-Induced Damage in Optical Materials 2018: 50th Anniversary Conference, 1080512 (16 November 2018);

Back to Top