Development and characterization of a broad-bandwidth polarization-insensitive subwavelength optical device

The optical transmission through subwavelength apertures in a metal film has been found to be enhanced by several orders of magnitude. In this paper we report a method for controlling the polarization sensitivity and the transmission bandwidth of the extraordinary optical transmission. This method focuses on controlling the surface plasmon resonances and localized surface plasmon resonances which lead to the extraordinary transmission. Two results are obtained in this study. First, the maximum peak shift of the wavelength of 80 nm resulting from polarization change can be reduced to 3 nm; in other words, the polarization-sensitive nature of the extraordinary transmission can be turned into a polarization-insensitive one. Second, the transmission bandwidth can be broadened to 150% under the extraordinary transmission conditions.