Yb-laser-based sub-60fs Mid-Infrared Source Tunable from 2.5μm to 10μm

Abstract

Femtosecond pulses in the mid-infrared are essential in numerous ultrafast spectroscopy methods [1] - [3] . Yb-based DPSS laser systems are attractive drivers of nonlinear optics-based mid-IR sources because of high stability and capability to operate at high repetition rate and average power [4] . However, using standard nonlinear conversion schemes results in mid-IR pulses with ~200fs durations and ~100 cm -1 bandwidths [4] , which may be insufficient for certain applications. We present a dual-channel optical parametric amplifier (OPA) and difference frequency generation (DFG) setup carefully designed to produce short mid-IR pulses in a broad tuning range. We demonstrate gapless coverage of 2.5-10μm with sub-60fs pulses. Up to 2W mid-IR output power at 2.7μm and 0.45W at 10μm is achieved using a commercial 80W pump laser.