Light transmission through nanostructured metal films: numerical modeling and experiment

So far, the numerical modeling of the nanostructures in metal films has considered perfect conductors, or used effective surface impedance boundary conditions. Here, we incorporate the Drude response of metals within a finite-difference time-domain (FDTD) method, which allows for modeling the electromagnetic field propagation within the metal. Numerical modeling was performed for a specific 2D structure consisting of a slit surrounded by a periodic array of grooves in a thin gold film. By using the FDTD method with a realistic metal response, we can account for tunneling through the metal film, which was not shown with past models. The modeled structures were fabricated using focused-ion beam milling.