High-power picosecond mid-infrared optical parametric amplifier for infrared Raman spectroscopy

A high-power (50-MW), kilohertz, picosecond, mid-IR optical parametric amplifier that is pumped by an amplified Ti:sapphire laser and also produces a fixed-frequency visible pulse is described. Mid-IR pulse energies of 40-55 mu J with 0.6-0.8-ps durations and 35-cm(-1) bandwidths are reported in the 3650-2800-cm(-1) range. The combination of picosecond mid-IR and visible pulses is useful for two-color spectroscopies, which require simultaneous time and frequency resolution. To illustrate the above, we present vibrational relaxation data for the polyatomic molecule nitromethane, using time-resolved infrared Raman spectroscopy. (C) 1997 Optical Society of America.