Abstract

Amplification resulting from two-wave mixing of optical signals occurs in nearly degenerate or, equivalently, transient conditions, subject to the restriction that the response of the nonlinear material to the incident wave is not instantaneous. Recent work has focused on Kerrlike materials.¹ In the present study, we explore the time dynamics of two-wave mixing in a Kerrlike (Δn ∝ I), but nonlocal, plasma where the required delay process is induced either by a simple collision mechanism or by Landau damping. Maxwell's equations are coupled to the appropriate governing equations of the plasma, followed by linearization based on a strong undepleted pump wave and simplification by the slowly varying envelope approximation. Two plasma models are explored: (i) a warm collisional plasma, and (ii) a Vlasov plasma to simulate the effects of Landau damping. In each case, the resulting equations are solved via Laplace transform techniques. In the presence of a delay mechanism, the two-wave mixing geometry produces spatial amplification of an applied probe wave in transient (or nearly degenerate) conditions. An enhancement of the plasma response occurs when a moving intensity grating, propagating at a velocity of a natural mode of the plasma, is generated. This enhancement of two-wave mixing can be considered a form of stimulated Brillouin scattering.

© 1989 Optical Society of America