Theoretical model for coupled solid-state lasers

Abstract

We consider the theoretical description of two parallel and adjacent lasers in a monolitic crystal. Starting from first principles, a semiclassical theory is developed. A system of nonlinear differential equations for both lasers field and inversion is obtained. In the weak-coupling limit, we show that the coupling between the laser fields is linear. Moreover, the coupling strength is measured by a complex coefficient: (i) the real part is related to the overlap of fields with a weight given by the pump beam profile, while (ii) the imaginary part is associated with the refractive index structure created inside the crystal. The parameters are defined explicitly in terms of pump, index, and ``cavity eigenmodes'' structures. The resulting system of two coupled nonlinear oscillators is analyzed. The effect of this coupling on the laser's dynamical behaviors, like stable synchronization and beating phenomena, is studied.