Resonant grating waveguide structures

TLDR

Resonant waveguide grating structures exhibit a phenomenon where incident light partially transmits and partially diffracts into the waveguide, and at a specific wavelength and angle the trapped light destructively interferes, resulting in zero transmission. The paper reviews prior investigations and develops analytic and numerical models to evaluate resonance as a function of structural geometry, optical parameters, and incident radiation. Analytic and numerical models are presented to assess resonance based on the geometric and optical parameters of the structures and the characteristics of the incident radiation.

Abstract

Under certain conditions, a resonance phenomenon can occur in waveguide grating structures. Such structures have multilayer configuration, the most basic of which is comprised of a substrate, a thin dielectric layer or semiconductor waveguide layer, and an additional transparent layer in which a grating is etched. When such a structure is illuminated with an incident light beam, part of the beam is directly transmitted and part is diffracted and subsequently trapped in the waveguide layer. Some of the trapped light is then rediffracted outwards, so that it interferes destructively with the transmitted part of the light beam. At a specific wavelength and angular orientation of the incident beam, the structure "resonates"; namely, complete interference occurs and no light is transmitted. This paper reviews previous investigations on the resonance phenomena and presents analytic and numerical models for evaluating the resonance as a function of the geometric and optical parameters of the structures and incident radiation.