Efficient pseudo-spectral time-domain method for light scattering by realistic aerosols

A robust and powerful technique known as the pseudo-spectral time-domain (PSTD) method is applied to the study of the scattering properties of nonspherical inhomogeneous particles. In this method, the higher order spatial derivative approximation is represented by the fast Fourier transform (FFT). In contrast to the conventional finite-difference time-domain (FDTD) method, PSTD is more efficient because a coarse grid spatial resolution (3-6 cells per wavelength) can be applied for the same accuracy. Thus, it is possible to use PSTD to accurately study the light scattering properties of realistic aerosols with large size parameters. In this study, the PSTD method is first validated for the case of light scattering by spheres for which analytical solutions are available. Furthermore, the PSTD solutions are compared with the T-matrix counterparts for light scattering by spheroids and circular cylinders. In the present calculations, two refractive indices are selected, which represent marine aerosols (1.38 + i3.9×10-9) and soots (1.75 + i0.44), respectively.