Transmission characteristics of a plasmonic Bragg reflector based on a metal-embedded slot structure

A 3D plasmonic Bragg grating formed by a periodic arrangement of metal in a slot waveguide is proposed and investigated. The metal-embedded slot structure supports two different modes: the symmetric mode and the asymmetric mode. The symmetric mode is chosen to design a Bragg grating for long range propagation with compact modal size, and the Bragg grating demonstrates a wide stop-band (1520–1595 nm) with a 1‰ transmission of only 40 periods. Moreover, a defect is introduced into the Bragg grating. Simulated results show that with the tapered metal, this defect mode exhibits a narrow-band filtering effect of a relatively high Q -factor ( Q = 454.7). The performance of the proposed structures is simulated by the finite-difference-time-domain method. In addition, by changing the polymer refractive index, this defect mode filtering effect can be reconfigured, which shows good potential for sensors and filters.