High-power, dual-wavelength femtosecond LiB₃O₅ optical parametric oscillator pumped by fiber laser.

We reported a dual-wavelength femtosecond optical parametric oscillator (OPO) based on a temperature-tuned LiB₃O₅ crystal. The OPO was synchronously pumped by a frequency-doubled, mode-locked Yb-fiber laser amplifier, providing a 520 nm pump laser with durations of 250 fs at a repetition rate of 57 MHz. High efficiency and dual-wavelength operation are obtained over the ranges of 658-846 nm and 2.45-1.35 μm. The observed dual-wavelength tuning is in agreement with the values predicted by numerical simulation. Moreover, a sum-frequency yellow laser of the longer signal and idler tunable from 555 to 623 nm with practical power is achieved. With an 8% output coupler, the maximum signal output power is 390 mW pumped at 3 W with dual-wavelength operation, while the maximum power of sum-frequency generation is 110 mW at 590 nm.