Spatial differentiation of optical beams using a resonant metal-dielectric-metal structure

Abstract

The development and investigation of novel photonic structures for the differentiation of optical signals, which are considered as promising building blocks for the optoelectronic information processing devices, has attracted considerable attention in recent years. In this tutorial, we discuss the optical computation of the spatial derivatives of the profile of a 2D optical beam impinging on a resonant diffractive structure. As a diffentiator example, we consider a simple resonant metal-dielectric-metal (MDM) structure consisting of an upper metal layer, a dielectric layer, and a metal substrate. Using the multiple wave interference model, we prove that the reflection coefficient of the MDM structure may strictly vanish, which enables obtaining high-quality differentiation. The rigorous numerical simulation results demonstrate the possibility of optical computation of the first derivative of the incident beam profile in the case of oblique incidence, and of the second derivative in the case of normal incidence. The presented results may find application in novel analog optical computing and optical information processing systems.