Understanding and predicting the damage performance of KD _xH _2-xPO ₄ crystals under simultaneous exposure to 532- and 355-nm pulses

Laser-induced initiation of bulk damage sites in K Dx H2-x P O4 crystals is investigated under simultaneous exposure to 532 and 355 nm nanosecond laser pulses in order to simulate the operational conditions during harmonic conversion as well as probe the damage mechanisms. The results demonstrate synergetic damage effects under the dual-wavelength excitation. Furthermore, the damage performance is directly related to and can be predicted from the damage performance at each wavelength separately. The measured relative effective absorption coefficients at the two wavelengths are found to depend on the laser fluence.