Multimode operation of a cw CO2 laser with an unstable cavity in the presence of phase inhomogeneities

A numerical investigation of a fast-flow CO₂ laser with an unstable cavity and with phase inhomogeneities demonstrated that two stable mutimode lasing regimes can exist. In each regime the lasing characteristics depend continuously, in certain intervals, on the amplitude of phase inhomogeneities. The existence of two regimes may give rise to transients as a result of small changes in the cavity phase inhomogeneities.