Special Features of the Acoustically Distributed Feedback Lasers Based on Gyrotropic Cubic Crystals

The oscillation conditions were determined for the distributed feedback lasers based on gyrotropic cubic crystals. The frequencies of clockwise (counterclockwise) polarized longitudinal eigenmodes decrease (increase) by ω ρ = ρc/n (ρ is the specific optical rotation of the crystal, n is the index of refraction, с is the speed of light in vacuum) relative to the Bragg frequency 㲐 = πс/Λп (Λ is the phase grating period). The gain threshold is higher for the clockwise than for the counterclockwise-polarized waves.