Broadly tunable picosecond narrowband pulses in a periodically-poled KTiOPO(4) parametric amplifier

A picosecond double-pass periodically poled KTiOPO(4) (PPKTP) noncollinear parametric amplifier that delivers tunable and narrowband outputs between 1.1 mum and 1.65 mum is reported. The seed source is an ultra-broadband emitting PPKTP collinear parametric generator, which is spectrally narrowed, from a bandwidth of 80 THz to about 0.3 THz, by a Fourier-filtering arrangement. A parametric gain of 70 dB is measured with preserved spectral bandwidth, resulting in a signal energy of 6.5 muJ at a pump energy of 60 muJ from the Ti:sapphire regenerative amplifier. The total energy-budget for the setup is less than 100 muJ with an optical-to-optical efficiency of 12 %. This particular system is scalable to even lower pump energies by tighter focusing arrangements.