Broadband extraordinary optical transmission through tapered metallic slits array embedded with rectangular cavities

To achieve nonresonant broadband extraordinary optical transmission (EOT), tapered metallic slits array embedded with rectangular cavities structure was proposed and its transmission properties were investigated using the finite element method (FEM). The results show that tapered metallic slits array embedded with rectangular cavities can achieve broadband and wide-angle enhanced transmission in the infrared and the light is strongly localized enhanced at the slit exits, in contrast with straight slits structure. The phenomenon was described with a transmission line model. In addition, the effects of incident polarization, the entrance width of the slit, and the centers misalignment of the tapered slits on the transmission property were also studied. These results would be helpful for optical signal transmission and the designing near field light harvesting devices with broadband and strong transmission.