Far-Infrared Laser Lines from Optically Pumped CH3OH

Abstract

Methyl alcohol illustrates in a remarkable way the potential of the optical pumping technique. It was recognized early as a source of strong FIR lasing by Chang et al. (1970). Since then, hundreds of lines have been generated by the various isotopic modifications of the molecule. At the present time, normal CH30H has generated more than 300 lines, ranging from 19 ~m to 1223 ~m, in CW or quasi-CW operation. About 200 of these lines have been pumped by conventional C02 lasers using the normal isotopic modification of C02 (Tables Ia and II). Information on wavelength, relative polarization, relative power, and pressure is generally available.Also, precise FIR frequency measurements are at our disposal for 98 FIR lines (Petersen et al., 1980 and unpublished). This is helpful for the assignment of the lines and provides a comb of precise reference FIR frequencies from 245 GHz to 8 THz, using a single laser source.