High-repetition-rate, all-solid-state, Ti:sapphire-pumped optical parametric oscillator for the mid-infrared

We report a low-pump-threshold, all-solid-state subpicosecond optical parametric oscillator (OPO) for the mid-infrared based on periodically poled LiNbO3 and synchronously pumped by a mode-locked Ti:sapphire laser. Using a semimonolithic cavity design and hemispherical focusing, pump power thresholds of 17 mW and mid-infrared idler powers of 64 mW have been obtained in the 3.9-6 mu m spectral range in a simple, practical, and compact configuration at pulse repetition rates of up to 322 MHz. The OPO delivers a signal output power of up to 280 mW at similar to 35% extraction efficiency and can provide transform-limited signal pulses with durations of 0.4 ps over the spectral range of 1.00-1.14 mu m. (C) 2000 American Institute of Physics. [S0003-6951(00)00530-1].