Enhancing resonant tunnelling of a wide beam through vertical slow-light photonic-crystal waveguides (SPCWs) with an assistant horizontal SPCW.
Enhancement of resonant tunnelling of a wide beam through vertical subwavelength slow-light photonic-crystal waveguides (SPCWs) is considered. An assistant horizontal SPCW with a thin side wall, whose guided modes have small propagation constants, is used as an input coupler for the vertical SPCW, and the two SPCWs form a compact composite structure to enhance drastically the resonant tunnelling. An incident wide beam can excite strongly the guided modes of the horizontal SPCW, and then resonantly tunnels through the vertical SPCW efficiently. To further improve the resonant tunnelling of a wide beam, a periodic array of vertical SPCWs (with a horizontal SPCW as an input coupler) is also investigated. With this periodic structure, a wide beam can be transmitted nearly completely. When a wide beam tunnels through the vertical SPCWs efficiently, the excited fields inside the SPCWs are very strong.
Jin
Yi
Y
Centre for Optical and Electromagnetic Research, Zhejiang University, Hangzhou 310027, China.
He
Sailing
S