Abstract: Propagation of a weak probe optical beam through a three-level medium pumped with a microwave strong beam is numerically studied. P-scheme of transitions under the conditions providing the amplification of the probe field without inversion is taken to calculate the atomic polarization which enters the paraxial wave equations. Diffraction and self-action of beams due to nonlinear absorption and refraction are properly taken into account. These effects together with linear absorption and refraction form a complex distribution of gain across the beams. As a result the amplified beam acquires ring transverse patterns and slight asymmetry in the frequency characteristics.!10
展开▼
