A laser infrared source of nanosecond pulses tunable from 1.4 to 22 μm

A reliable source of coherent ns pulses of infrared radiation continuously tunable between 1.4 and 22 μm has been designed and built with the aim of developing a time-resolved infrared vibrational spectroscopy for species adsorbed on surfaces. The system is based on a Nd: YAG-laser and dye-laser combination which drive difference mixing processes in a sequence of nonlinear optical crystals (two LiNbO3, and a CdSe or AgGaS2). The system operates at MW peak power levels above 2500 cm-1, at kW power levels from 1000-2500 cm-1 and at 10-100 W levels down to 450 cm-1. These power levels are certainly sufficient for spectroscopic purposes, and at shorter wavelengths molecular pumping and applications requiring high-power should be possible. Vibrational spectra of a monolayer of CO adsorbed on Pt in an electrochemical cell have been obtained in an initial application of this source. © 1986 Springer-Verlag.