Mid-IR short-pulse OPCPA with micro-Joule energy at 100 kHz

We present a novel mid-IR source based on optical parametric chirped pulse amplification (OPCPA) generating 96 fs pulses (9.0 cycles) at 3.2 mu m with an energy of 1.2 mu J, at a repetition rate of 100 kHz. The amplified spectrum supports a minimum Fourier transform limited pulse duration of 45 fs, or 4.2 cycles. Our use of OPCPA allows the direct amplification of few-cycle pulses at this mid-IR wavelength, and is inherently scalable to higher energies. The seed source for the system is based on difference frequency generation (DFG) between two outputs of the same fibre laser: this source is expected to be intrinsically CEP stable. (C) 2009 Optical Society of America