Controlling enhanced transmission through semiconductor gratings with subwavelength slits by a magnetic field: Numerical and analytical results

We exploit the change in the permittivity tensor of a conductor by a static magnetic field as a handle to control enhanced transmission in a semiconductor grating. Numerically, results of rigorous coupled-wave analysis (RCWA) incorporating the tensorial permittivity reveal that zeroth order transmission peaks at normal incidence can be shifted by about 15% to longer wavelengths and the peak values of transmission readily doubled when a moderate magnetic field is applied. Analytically, a single-mode theory incorporating anisotropy is developed and results are in quantitative agreement with RCWA, indicating that the tunability in the transmission stems from the waveguide mode.