FDTD analysis of three-dimensional light-beam scattering from the magneto-optical disk structure

This paper implements some new techniques to analyze the light beam scattering from a magneto-optical (MO) disk using the three-dimensional finite-difference time-domain (FDTD) method. The anisotropic FDTD update equations are implemented to calculate the propagation of a coherent monochromatic light in the MO material. An anisotropic absorbing boundary condition based on Berenger's perfectly matched layer (PML) concept is also developed. The Gaussian incident light beam is introduced into FDTD computation region exactly by using equivalent electric and magnetic currents. The scattering pattern of light beam from the MO disk is computed and in part compared with that obtained by using the boundary element method. The scattering patterns by the circular recording bit of different radius are calculated to indicate the optimum radius of the recording bit.