Continuous Stokes self-scattering of an optical pulse in a uniaxial crystal in the case of Zakharov–Benney resonance

A new mechanism of the continuous frequency down-conversion of a pulse propagating in a uniaxial crystal under conditions of the Zakharov–Benney resonance between its ordinary and extraordinary components is proposed. Unlike stimulated Raman self-scattering, here the red frequency shift of the ordinary component saturates, achieving its maximum value at some propagation length, which is proportional to the input pulse intensity. The ordinary component generates an ultimately short single pulse of the extraordinary wave propagating in the soliton regime. It is shown that this effect can be observed only in a crystal with the positive birefringence.