Competition between orthogonally polarized modes in a two-mode CO2 laser

For the first time an experimental and theoretical investigation was made of the interaction of two linearly and orthogonally polarized modes in a CO₂ laser utilizing a discrete vibrational–rotational transition. The influence of the field characteristics of the modes of a phase–anisotropic resonator and of the active medium on the intermode competition was considered. Stable two-mode lasing was obtained when the intermode separation was varied from 0.3 to 70 MHz, the widest two-mode lasing range being 80 MHz.