CW CO 2 laser damage in optical components: thermal modeling and surface characterization

Abstract

This paper reports progress towards characterizing the laser induced damage threshold (LIDT) for zinc selenide and copper components in CW/C02 laser optical systems. The work has been undertaken by industrial partners and research centres supported by the CRAFT initiative of the European Commission.Specimen surfaces have been characterized by a wide range of experimental methods, including absorption calorimetry. Thermal modelling on the basis of these observations indicates that the temperature rise in irradiated components is dominated by surface absorption, and that the maximum temperature rise is proportional to the ratio of the total power P to focal spot size d rather than to the areal power density.A CW/C02 laser damage facility has been constructed by one of the industrial partners. Preliminary. experiments have determined P/d values at the LIDT an order of magnitude less than those predicted by the measured level of surface absorption. SPIE Vol. 2714 / 281 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 06/15/2016 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

Limits of performance: CW laser damage

“…[14][15][16][17] Each portion of the structure will be examined and the contributions to laser damage evaluated. Although much fewer than previous publications, some assumptions have been made to simplify the model and predict results more easily.…”