Generation of tunable picosecond pulses in the vibrational infrared by stimulated electronic Raman scattering of rhodamine-dye-laser pulses from the 6s-5d cesium transition

The first reported use of a rhodamine-dye laser to generate tunable high-power picosecond pulses in the vibrational infrared is described. By using stimulated electronic Raman scattering from the 6_s-5d transition in a superheated cesium vapor, we have shifted I-psec pulses from an amplified rhodamine-dye laser (568-590 nm) to 3040-2320 cm^-1 (3.3-4.3 µm). Somewhat longer pulses have been shifted to 1950 cm^-1 (5.1 µm). Peak infrared energies of 11 µJ, representing a quantum efficiency of 4.6%, were obtained at a 10-Hz repetition rate. Tuning to longer wavelengths with short pulses is limited by nonlinear processes but should be possible by further reductions of cesium dimer effects.