Simulation of Infrared Bandpass Filter Using Three-dimensional FDTD Method

In this research,we developed a three-dimensional finite-difference-time-domain algorithm that incorporated the Lorentz-Drude model through the use of Ztransform technique.This algorithm was used to compute the spectral response of infrared bandpass filters which consisted of the openings of cross-shaped structures in a thin gold film.In creating structures,a graphical user interface was built using Matlab development environment.The created structures were then simulated by running the simulation code written in Fortran.It was observed that cross-shaped structures with large center-broadening effect yielded the highest transmission intensity among the structures that were simulated.With a transmittance of approximately 80% at wavelength 1.2 μm.