Numerical methods for the bidimensional Maxwell–Bloch equations in nonlinear crystals

Two numerical schemes are developed for solutions of the bidimensional Maxwell–Bloch equations in nonlinear optical crystals. The Maxwell–Bloch model was recently extended [C. Besse, B. Bidégaray, A. Bourgeade, P. Degond, O. Saut, A Maxwell–Bloch model with discrete symmetries for wave propagation in nonlinear crystals: an application to KDP, M2AN Math. Model. Numer. Anal. 38 (2) (2004) 321–344] to treat anisotropic materials like nonlinear crystals. This semi-classical model seems to be adequate to describe the wave–matter interaction of ultrashort pulses in nonlinear crystals [A. Bourgeade, O. Saut, Comparison between the Maxwell–Bloch and two nonlinear maxwell models for ultrashort pulses propagation in nonlinear crystals, submitted (2004)] as it is closer to the physics than most macroscopic models. A bidimensional finite-difference-time-domain scheme, adapted from Yee [IEEE Trans. Antennas Propag. AP-14 (1966) 302–307], was already developed in [O. Saut, Bidimensional study of the Maxwell–Bloch model in a nonlinear crystal, submitted (2004)]. This scheme yields very expensive computations. In this paper, we present two numerical schemes much more efficient with their relative advantages and drawbacks.