Pseudospectral time-domain methods for modeling optical wave propagation in second-order nonlinear materials

Frequency conversion in second-order nonlinear materials is sensitive to the phase velocities of interacting optical waves. Accurate modeling of such problems with the finite-difference time-domain method requires extremely fine grid resolutions to minimize numerical dispersion errors. We propose an alternative approach based on a pseudospectral time-domain (PSTD) method for solving the nonlinear Maxwell’s equations. Lowdispersion PSTD schemes with secondand fourth-order time stepping are developed and investigated. Benchmark simulations of second-harmonic generation (SHG) demonstrate that the PSTD schemes offer significant improvements in computational efficiency and accuracy. We demonstrate use of these schemes by modeling SHG in a nonlinear grating illuminated at an oblique angle, where phase matching is achieved in two dimensions. © 2004 Optical Society of America OCIS codes: 190.0190, 190.2620, 000.4430