Blue light generation in bulk periodically domain-inverted lithium niobate crystals

We report the generation of blue light in bulk domain-inverted lithium niobate by 3rd order quasi-phase-matching. High voltage pulses were used to induce periodic domain inversion in z-cut plates. The smallest domain width we have attempted to invert in these initial experiments is 4 µm, and inversion was achieved without difficulty. Since the field strength required for inversion is about 25 kV/mm along the z-axis and our high-voltage switch gives a maximum output of 5.5 kV, we are limited to processing 0.1 mm and 0.2 mm thick plates