Extraordinary Optical Transmission of Broadband Through Tapered Multilayer Slits

The nonresonant, enhanced optical transmission of subwavelength metallic slits on a thin film is significant in broadband light harvesting devices. To improve transmission efficiency, this paper established tapered multilayer slits in which thin dielectric layers are sandwiched between two metallic layers. The transmission properties of these slits are then investigated using the finite element method. Results show that transmission is improved in the tapered multilayer slits relative to that in the tapered monolayer slits. The effects of structural parameters on these transmission properties are also examined.