Key points are not available for this paper at this time.
In this work we introduce several developments of unique optics with specified reflected wave front error (RWE) of λ/10 (63nm P.V) before exposure to at least 40 seconds 200kilowatt laser power at 1064nm as well as during exposure. A 10μm thick broadband dielectric high reflection (HR) coating was deposited on a 400mm diameter fused-silica substrate. A 0.4% coating uniformity was achieved which is equivalent to 40nm P.V RWE. To compensate the RWE introduced by the stressed HR coating, a unique anti-reflection (AR) coating was deposited on the backside resulting in total RWE of less than λ/10 (63nm P.V). A post deposition thermal process resulted in a 1.2% spectrum red shift, absorption reduction from 20ppm to 3ppm and no change in the RWE. In a second case, a 130mm dichroic mirror with rigid tolerance limiting the acceptable spectral red shift post thermal treatment, was exposed to low temperature process, reducing absorption from ~25ppm to 6ppm. In a third case, a scanning mirror (R>99.995%) with high specific stiffness substrate material (absorbing) and λ/10 RWE measured during exposure to 72kW/cm2 laser for 40 seconds is discussed. Keywords: Ion beam sputtering, laser damage threshold, high refection coating, anti-reflection coating, stress
Kassis et al. (Mon,) studied this question.