200-mW-average power ultraviolet generation at 0193 μm in K_2Al_2B_2O_7

K2Al2B2O7 has been found to be phase matchable for type-1 sum-frequency generation (SFG) at 0.193 microm by mixing the Nd:YAG laser wavelength at 1.0642 microm and the SFG output of the RbTiOAsO4 optical parametric oscillator tuned at 0.2358 microm. An average power of 200 mW at 10 kHz was obtained in a 7-mm-long crystal. In addition, the Sellmeier equations and the thermo-optic dispersion formula, which predict well the phase-matching conditions and temperature phase-matching bandwidths (FWHM) for second-harmonic generation and SFG in the 0.193-0.669-microm range, are presented.