The PSTD algorithm: A time-domain method requiring only two cells per wavelength

A pseudospectral time-domain (PSTD) method is developed for solutions of Maxwell's equations. It uses the fast Fourier transform (FFT), instead of finite differences on conventional finite-difference–time-domain (FDTD) methods, to represent spatial derivatives. Because the Fourier transform has an infinite order of accuracy, only two cells per wavelength are required, compared to 8–16 cells per wavelength required by the FDTD method for the same accuracy. The wraparound effect, a major limitation caused by the periodicity assumed in the FFT, is removed by using Berenger's perfectly matched layers. The PSTD method is a factor of 4D–8D more efficient than the FDTD methods (D is the dimensionality).