Optical parametric amplification of carrier-envelope phase-stabilized mid-infrared pulses generated by intra-pulse difference frequency generation.

Abstract

We report on a wavelength-tunable optical parametric amplifier (OPA) from 2.7 to 3.8 μm seeded with carrier-envelope phase (CEP) stabilized pulses generated by intra-pulse difference frequency generation (DFG) using a commercial Yb:KGW chirped-pulse amplifier. The Yb:KGW laser's output pulses are spectrally broadened in two-stage multi-plate pulse compression from 0.8 to 1.25 μm, which are compressed down to a sub-two-cycle duration of 6.5 fs using chirp mirrors. CEP-stabilized mid-infrared pulses are produced in intra-pulse DFG of the spectrally broaden pulses around 1.03 μm and parametrically amplified in KTiOAsO4 crystals. The output energy and temporal duration of the OPA output pulses range from 31 to 56 μJ and from 102 to 203 fs, respectively. The root mean square value of their CEP errors is measured to be 101 mrad.