Influence of an axial magnetic field on the frequency shifts in a two-mode He–Ne/CH4 laser

An experimental and theoretical study was made of the influence of an axial magnetic field on the frequency shifts in a two-mode He–Ne/CH₄ laser with a controlled intermode coupling. It was found that by subjecting the active medium to a relatively weak axial magnetic field (20–100 Oe) one could eliminate the shift of a resonance peak relative to the central frequency of an absorption line. These results represent a further improvement in the frequency reproducibility of two-mode He–Ne/CH₄ lasers.