A 16-µm Radiation Source Utilizing Four-Wave Mixing in Cooled Parahydrogen Gas.

Improvements in a 16-µm radiation source based upon the combined effects of stimulated rotational Raman scattering and resonantly enhanced four-wave mixing in parahydrogen gas are described. For this source, the input waves of which are provided by temporally and spatially coincident pulsed beams from a ruby and CO 2 TEA laser, it was found that cooling the parahydrogen gas from 300 K to <100 K, at constant molecular density, increased the output at 16 μm by roughly a factor 4. The maximum output was measured to be ~ 40 μJ/pulse, which is near the theoretical limit for the 2.5 MW CO 2 laser intensities that were applied. © 1977, IEEE. All rights reserved.