Analysis of Bragg reflectors and waveguides based on metal-dielectric stacks

Abstract

Bragg reflectors and waveguides, as a kind of photonic band gap (PBG) structures, receive much attention during recent years and have been used in a wide variety of photonic devices. However, most of these analysis and designs are based on all-dielectric materials. Though there are some attempts to incorporate metals into PBG structures, most of them concentrate on two- or three-dimensional structures where only numerical methods are available and the physical meaning can be hard to interpret. To better understand the dispersive properties and facilitate the design of metal-dielectric Bragg structures, an analytical approach based on transfer matrix method and complex analysis was proposed. Band gaps and their associated losses of Bragg reflectors based on periodic metal-dielectric stacks operating at the optical communication frequency were obtained rigorously. Different mechanisms of light transmission within pass bands including propagating and surface modes were discussed. A symmetric PBG slab waveguide consisting of a defect layer sandwiched between two semi-infinite Bragg reflectors were also investigated and mode dispersion curves were obtained with the help of transverse resonance condition. These results will provide an understanding of band gap effects of metal-dielectric PBG structures and serve as a reference for practical design of devices.