RADIATION EFFECTS ON LASER CRYSTALS FOR SPACE APPLICATIONS

In the frame of a research program supported by ESA (European Space Agency) a solid state laser for space based Lidar (light detection and ranging) application has been designed and is now being completed. This device has been designed to operate for three years on the ESA polar platform at the altitude of 800 km. In the space environment the laser optical components will be exposed to a radiation field whose effects on the optical properties and laser performance should be estimated. In this work the radiation environment is simulated by using a proton beam provided by a 3.5 MV tandem VdG accelerator in order to study the radiation effects on the optical transmission coefficients of four different laser crystals: Nd:YAG (laser active medium), BBO, KD*P and lithium niobate (for Q-switch and harmonic generation). In the present paper the peculiar experimental setup for crystal irradiations is described and results about radiation effects are presented and discussed.