Significant increase of UV reflectivity of SiC galvanometer mirror scanners for the high-power laser applications

Abstract

Silicon carbide (SiC) galvanometer mirror scanners are widely used for high-speed laser scanning systems engineering. For bare SiC galvo-scanners, the working range and laser induced damage threshold (LIDT) are limited. In order to overcome these limits special surface enhancement should be done. In present research, an optimized multilayer coating approach was suggested. This method ensures a significant increase in SiC ultraviolet (UV) range reflectivity. The SiC reflectivity was enhanced from 25% up to the 98.5% at the 355 nm wavelength for the angles of reflection from 34 ° to 56 °. Moreover, the multilayer coating designs suitable for the high-power laser systems was optimized and deposited on SiC. What is more important, it was demonstrated how to reach better flatness of the SiC without affecting the coating roughness. Finally, the coating has passed the high-temperature annealing, humidity chamber and scotch-tape tests needed for final application.