Laser-induced damage tests under multiple wavelength irradiation of ATLID TXA optics for ESA-satellite mission EarthCare

Abstract

A setup was developed at Laser-Laboratorium that allows determination of LIDT data under simultaneous 1064nm, 532nm and 355nm irradiation (3l), in order to investigate the influence of combined irradiation of specific elements with multiple wavelengths. Utilizing a fully characterized test laser beam and a well defined sample environment, 10.000-on-1 LIDT data of high-reflecting mirrors (AOI 45°) in vacuum were determined both at multiple wavelengths (3l) and at 355nm alone. In addition, a test optics (HR355, 45°, ambient conditions) was irradiated for 150 million pulses at (3l) at a fixed fluence of 2 J/cm 2 as a certification test.

Low-stress soldering technique used to assemble an optical system for aerospace missions

“…Sputtered three layer systems using titanium as an adhesion layer, a platinum layer as a diffusion barrier, and a noble gold finish to prevent oxidization and acting as a wetting surface provide superb conditions for wetting of liquid solder droplets. Optical elements used for space applications such as those used at the European Space Agency LIDAR (Light detection and raging) EarthCare Mission whose aim is to monitor molecular and particle-based back scattering to analyze atmosphere composition needs to be fixated in a robust and stable way without altering the optical performances [5] but also assuring high levels of cleanliness in order to avoid laser induced contamination (LIC) and laser induced damage (LIDT) [6]. For our purpose, we investigated the assembly of a high grade fused silica lens (see L1 in Fig.…”