Numerical treatment of UV-pumped, white-light-seeded single-pass noncollinear parametric amplifiers

A technique for numerically simulating second-order nonlinear interactions of light waves modulated spatially and temporally in both amplitude and pha se in a uniaxial medium with arbitrary polarization and propagation directi ons is presented. A three-dimensional grid technique that automatically ada pts grid parameters to the evolving sampled amplitudes by means of an analy tical fit function is described. By means of spatiotemporal split-step fast -Fourier-transform propagation, diffraction and group-velocity dispersion c an be included. We employ this technique for femtosecond noncollinear white -light-seeded parametric amplification in experimental designs presented ea rlier [Opt. Lett. 22, 1494 (1997); 23, 1283 (1998)]. The dependence of phas e mismatch on signal wavelength provides a quantitative measure of the achr omaticity of phase matching. Our results indicate that the pump pulse chara cteristics and not phase mismatching limit the amplification and the bandwi dth of the parametric amplifier. (C) 1999 Optical Society of America [S0740 -3224(99)01509-X].