Spatial characteristics of a beam and quality of phase conjugation of radiation from a CO2 laser with InAs in its resonator

An investigation was made of the spatial characteristics of radiation from a CO₂ laser with InAs in a stable resonator. Inhomogeneities of the spatial distribution of the radiation intensity observed in the near-field zone were due to diffraction of the radiation by the smallest aperture inside the resonator because of formation of a nonlinear diverging lens in InAs. The beam emerging from the laser had the properties of a converging wave. In spite of the characteristics of the spatial distribution of the laser radiation, the system with InAs inside the resonator ensured a nearly 100% phase conjugation, i.e., the fronts of the waves counterpropagating in the resonator were conjugate.