Generation of carrier-envelope phase stabilized intense 1.5 cycle pulses at 1.75 μm.

A three-stage high conversion efficiency optical parametric amplifier (OPA) with passively stabilized carrier-envelope phase (CEP) is presented. After passing through an argon-filled hollow fiber and the dispersion compensator for pulse compression, CEP stabilized 0.7 mJ, 1.5 cycle laser pulses at 1.75 mu m center wavelength are obtained. Terahertz (THz) emission spectroscopy is adopted to determine the value of CEP, indicating an excellent long-term CEP stability. (C)2011 Optical Society of America