Optical properties of cascaded metal-dielectric-metal structures and their application to the differentiation of optical signals

Abstract

We consider optical properties of cascaded structures consisting of several sequentially placed three-layer metal-dielectric-metal (MDM) structures separated by homogeneous dielectric layers. Using the scattering matrix formalism, we demonstrate that by successively “combining” MDM structures possessing reflection zeros, one can obtain a zero of a required order in the reflection spectrum of the cascaded structure. The presence of a reflection zero of a required order with respect to the angular or spatial frequency enables utilizing cascaded MDM structures as optical differentiators implementing the computation of the derivative of a required order with respect to time or a spatial variable. The presented numerical simulation results confirm the correctness of the derived theoretical description of cascaded MDM structures and the possibility of their use as high-order optical differentiators. The obtained results may find application in analog optical computing and optical information processing systems.