Picosecond infrared optical parametric amplifier for nonlinear interface spectroscopy

A tunable, narrow bandwidth, high peak power picosecond infrared (IR) laser system is described. The pump source is a picosecond Ti:sapphire regenerative amplifier seeded by a picosecond Ti:sapphire oscillator. The pump bandwidth and pulse duration are tunable producing 4-5 ps, 5-4 cm(-1) pulses at 1 kHz. IR pulses are produced by optical parametric generation (OPG) followed by optical parametric amplification (OPA). Tuning is possible over the entire 1050-3300 nm region of the IR, with energies in excess of 15 muJ over most of the range. The temporal and spectral characteristics of the IR pulses are reviewed with a particular focus on the sources of bandwidth broadening in the OPG/OPA. Bandwidth optimization of the IR output is discussed. A spectral filtering scheme results in less than 15 cm(-1) IR bandwidth, suitable for nonlinear optical spectroscopic applications. (C) 2000 American Institute of Physics. [S0034-6748(00)02012-8].