42% Efficient Single-Pass cw Second-Harmonic Generation in Periodically Poled LiNbO3

We present a full-wafer fabrication process for periodically poled lithium niobate with a 6.5-μm domain period. Samples that were 53 mm long and 0.5 mm thick were obtained with this process for single-pass cw 1064-nm Nd:YAG second-harmonic generation. These samples exhibited 78% of the ideal nonlinear coefficient, had a measured conversion efficiency of 8.5% /W in the low-power limit, and produced 2.7 W of cw 532-nm output with 6.5 W of cw input, which corresponds to 42% power conversion efficiency.