Asymmetric optical transmission of a metallic grating-incorporated Fabry–Pérot cavity

Abstract

In this report, we show a structure of metallic grating–incorporated Fabry–Pérot (F–P) cavity demonstrating asymmetric optical transmission (AOT) for all transmission modes. The asymmetric transmission basically arises from asymmetric coupling and decoupling of resonant surface plasmons (SP) on both sides of the metallic grating with asymmetric media of different indices. Coupling of the SP mode with anti–resonance mode of the F–P cavity in orthogonal directions further optimizes transmission characteristics of the structure for asymmetric transmission. Particularly, a high contrast AOT is achieved by locating the SP resonance position at center of the anti–resonance band of the F–P cavity. Meanwhile, SP resonance modes induced at different interfaces/regions of the cavity structure influence the transmission properties. The AOT structure has no nanoapertures and critical requirements on profile of the grating surfaces for fabrication, and can be adapted to various optical systems.