Laser-diode-seeded single and double stage femtosecond optical parametric amplification in the mid-infrared

Tunable mid-infrared pulses are generated with a MgO:LiNbO3-based traveling -wave optical parametric amplifier in single and double stage operation reg ime pumped by a 1-kHz Ti:sapphire regenerative amplifier system. For the fi rst time to our knowledge a pulsed laser diode is successfully used in the femtosecond regime as a compact seed source at the signal wavelength where the tunability of the generated idler pulses can be realized by tuning the seed wavelength. Almost transform limited mid-infrared pulses as short as 1 30 and 160 fs with pulse energies as high as 5 and 15 mu J are produced nea r 3.5 mu m by the single and double stage scheme, respectively. The pulse t o pulse fluctuations in both cases do not exceed 2% which corresponds to th e stability of the pump source.