HIGH-POWER PICOSECOND MIDINFRARED 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 p roduces a fixed-frequency visible pulse is described. Mid-IR pulse ene rgies 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 picose cond mid-IR and visible pulses is useful for two-color spectroscopies, which require simultaneous time and frequency resolution. To illustra te the above, we present vibrational relaxation data for the polyatomi c molecule nitromethane, using time-resolved infrared Raman spectrosco py. (C) 1997 Optical Society of America.