Enhanced light transmission through a single subwavelength aperture in layered films consisting of metal and dielectric.

The light transmission through a single subwavelength aperture surrounded by periodic grooves in layered films consisting of Ag and transparent dielectric is analyzed numerically by finite difference time domain (FDTD) method. Results show that the transmission through the aperture in the composite films is strongly enhanced by the modulation of grooves on the transparent dielectric. Two models are employed to explain the mechanisms of transmission enhancement.