High-beam-quality, watt-level, widely tunable, mid-infrared OP-GaAs optical parametric oscillator

We demonstrate near-diffraction-limited performance from a mid-infrared, idler-resonant, fiber-laser-pumped, widely tunable, picosecond optical parametric oscillator (OPO) based on orientation-patterned gallium arsenide (OP-GaAs). The OP-GaAs OPO is synchronously pumped by a picosecond Tm:fiber master–oscillator-power-amplifier system. An OPO tuning range of 4394–6102 nm (idler) and 2997–3661 nm (signal) is achieved, with maximum average powers of 1.18 (idler, 5580 nm) and 0.51 W (signal, 3136 nm). The idler beam has M2 values of 1.06 (x-direction) by 1.03 (y-direction).