ABSTRACT

The development of mid-infrared (MIR) optically pumped gas lasers (MIROPLs) has been motivated by the concentration of molecular vibrational-rotational spectra in the MIR, with the consequential need for sources for spectroscopy and gas identification. Another source need is for selective excitation of vibrational modes to produce photochemical reactions, e.g. for isotope separation. The objective here is to provide an overview of the MIROPLs NH3 and C2H2 and their isotopic variations, primarily in the 8-20 µm range. We differentiate MIR from far-infrared (FIR) lasers in that the MIROPL transitions occur between different vibrational bands whereas FIROPL transitions generally occur on pure rotational transitions within a given vibrational mode at wavelengths mainly from 50 µm to 1 mm [1]. Much of the MIROPL development occurred in the 1970s and 1980s, and several reviews are available [2-6].