Self-oscillatory regimes in ring gas lasers

A theoretical investigation is made of self-oscillatory regimes in ring gas lasers when stimulated emission occurs near the center of the gain profile. Allowance is made for the back scattering of the opposite waves in a ring laser. An analysis is made of a regime of weak periodic modulation of the amplitudes of the opposite waves and of the difference between their phases near the boundary of the frequency locking region. A new type of pulse beats, characterized by periodic sudden jumps of the difference between the wave phases, is discovered. A study is made of a locking-beats hysteresis, when–depending on the initial conditions–either steady-state locking or beats are obtained.