Abstract

Unlike the dye laser case of previous bidirectional ring-laser studies^1,2 the CO₂ ring laser has a population relaxation rate that is much less than the polarization relaxation rate, thus providing additional physical variables as degrees of freedom for nonlinear dynamics. A complete model must include a set of equations coupling the field in both directions, the polarizations associated with each one, the spatially homogeneous population inversion, and the population grating formed by interference at the second spatial harmonic of the field. However, we show that a reduced set, obtained by adiabatic elimination of the polarization, can explain our experimental results in a CO₂ laser, because this variable has a high relaxation rate causing it to follow the slower dynamical evolution of the system.

© 1984 Optical Society of America