Intracavity Stark spectroscopy in optically pumped far-infrared lasers

Abstract
A simple method for performing intracavity Stark spectroscopy in optically pumped far-infrared lasers is described. A line from 12CH3OH is assigned and measured as E2 symmetry, (n, K, J):(0, 7, 20)–(0, 6, 19) = 81.654468(50)] cm−1, and a line from 13CH3OH as E1 symmetry, (1, 2, 4) – (1, 1, 3) = 81.657334(50) cm−1.