Everitt, HO; McCormick, RI; DeLucia, FC; Skatrud, DD, *DIAGNOSTICS, MODELING, AND DEMONSTRATION OF A COMPACT, TUNABLE FAR-INFRARED LASER.*
(January, 1987),
pp. 160 .
**Abstract:**

*A program of diagnostic studies and theoretical modeling has resulted in development of a tunable optically pumped far-infrared (FIR) laser that is very compact. The tunability of this laser comes about because it operates at pressures significantly higher than the maximum allowed by previously accepted theory. Typical dimensions for the compact FIR laser are a radius of 3 mm and a length of 150 mm. Because of the small diameter, the pump intensity is high even with modest pumping powers. At high pressures, the additional highly excited vibrational states become very important, and operation much above the cutoff pressure predicted by conventional theory becomes possible. The key element of the model, which explains the high-pressure operation of the laser is the inclusion of the additional highly excited vibrational states and the associated energy transfer processes. A very simple nonoptimized version of this laser has provided a tunability of 100 MHz. The model predicts that optimization of the device will produce 1000 MHz of tunability. Although **1**3CH//3F was used for all this work, the concept is general and would appear to apply to all diffusion-relaxed FIR lasers.*