First-order type II quasi-phase-matched UV generation in periodically poled KTP

Type II quasi-phase matching was employed for first-order frequency doubling of a single-longitudinal-mode Ti:sapphire laser in periodically poled KTP with a domain-inverted period of 9.01 mu m In a single-pass configuration, 0.44 mW of UV power at 398.8 nm was generated for an input of 780 mW, corresponding to a normalized conversion efficiency of 0.09% W-1 cm(-1). The nonlinear coefficient d(24) = 2.82 pm/V was deduced from the measurements. The larger grating period for the type II quasi-phase-matched second-harmonic-generation profess than for type I quasi-phase matching, lowers the fabrication constrains in the short-wavelength region and increases the acceptance bandwidth. (C) 1999 Optical Society of America OCIS codes: 160.4330, 190.2620.