Gaussian Beam-Based Hybrid Method for Quasi-Optical Systems

A hybrid method for analysis of electromagnetic propagation in passive quasi-optical or unbounded wave structures is presented. This method is a combination of Gaussian beam tracing (GBT), Gabor expansion, and the finite-difference time-domain method (FDTD). The input to a system is first expanded into a sum of Gaussian beams (GBs) using the Gabor expansion. The resultant GBs are launched inside the system and tracked/traced using the GBT. For structures where GBT is no longer applicable, the GBs form the input of an FDTD routine. The output of the FDTD can further be expanded using Gabor expansion, and the resultant beams can be propagated through the system.