Numerical study of multiple-pass effect by total internal reflection on second-harmonic conversion in KBe2BO3F2 crystal

Abstract

We apply total internal reflection to significantly extend the effective length of KBe2BO3F2 crystal. Thus the conversion efficiency for second-harmonic generation can be increased in principle. However, the total reflection also leads to an adverse effect on the conversion efficiency. Three multiple-pass configurations to extend the effective interaction length of the crystal are proposed and discussed in this paper. Numerical analysis shows that the double-pass configuration is more favorable for second-harmonic generation to below 200 nm. At the medium input intensity of 200 MW/cm(2), the configuration gives a conversion of 27.1% at the second-harmonic wavelength of 193 nm. A conversion of 45.2% is obtained as the input intensity is increased to a higher value of 500 MW/cm(2).