High-efficiency and narrow-linewidth operation of a two-crystal β-BaB2O4 optical parametric oscillator

We report a novel, two‐crystal, walkoff‐compensated optical parametric oscillator design using β‐BaB2O4, which significantly improves the performance of the device. The oscillator is pumped at 354.7 nm and is tunable throughout 0.42–2.3 μm with overall conversion efficiencies as high as 32%. We also report on demonstration of linewidth narrowing in the same β‐BaB2O4 oscillator, obtaining linewidths as narrow as 0.3 A.