High-efficiency third harmonic generation at 355nm based on La2CaB10O19.

La2CaB10O19 (LCB) crystals with size up to 55 × 35 × 25 mm3 have been grown by the top-seeded solution growth (TSSG) method. The refractive indices were accurately measured over the full transmission range, and the second-order nonlinear optical coefficients were determined by the Maker fringe technique. The phase-matching(PM) conditions were calculated for third-harmonic generation (THG) at different wavelengths. The THG experiments for type I and type II LCB crystals were performed. For type I LCB, a 355 nm UV light output of 5.0 mW corresponding to the conversion efficiency of 28.3% was generated under a picosecond Nd:YAG laser, and 16 W with the efficiency of 17.5% was generated under a nanosecond 1064 nm pumping source. For type II LCB, 3.5mW THG output with conversion efficiency of 21.1% was obtained under a picosecond Nd:YAG laser, and 7.6 W with the efficiency of 7.9% was generated under a nanosecond 1064 nm pumping source. The results indicated that the LCB crystal is a promising UV nonlinear optical material because of its good THG performance and nonhygroscopicity.