Efficient Second-Harmonic Generation of 340-nm Light in a 1.4-µm Periodically Poled Bulk MgO:LiNbO3

Ultra-violet second-harmonic generation in a 1.4 µm periodically poled MgO:LiNbO 3 is presented. Using a high-voltage multi-pulse application method, a first-order nonlinear grating with a period of 1.4 µm was fabricated over 10-mm interaction length in a 2-mm thick MgO:LiNbO 3 substrate. In a single pass configuration, cw 1.2 mW of ultraviolet light at 341.5 nm was successfully obtained for a fundamental power of 141 mW, corresponding to a normalized conversion efficiency of 5.4%/W.