Mixed type I and II BBO OPO pumped at 355 nm provides good beam quality, bandwidth, and efficiency

For ns 355nm pumped simple type II BBO OPOs, two problems still remain even after rotated cavity design 1,2. The first problem is that the efficiency is still low. The other problem is the requirement of adjusting the waveplate inserted in the rotated cavity during the wide tuning range. Here, we propose and demonstrate a simple prism rotated cavity1, which uses both a type I and a type II BBO crystals pumped at 355nm.