MODELLING OF STRESS-INDUCED BIREFRINGENCE IN VACUUM BARRIER LENSES

Stress-induced birefringence arising from vacuum loading in the spatial filter lenses of high-energy laser systems is responsible for laser beam depolarization which may decrease the frequency conversion efficiency significantly. In order to predict these effects, we have carried out coupled mechanical-optical calculations. At first, we validated our predictions with experimental results. Then a parametric study allowed us to explain the influence of the geometrical characteristics of the lenses. Our main result is that symmetric lenses lead to minimum birefringence.