High-NA 2D Image Edge Detection Using Tamm Plasmon Polaritons in Few-Layer Stratified Media

Abstract

Analog optical computing with nanophotonic devices has emerged as a promising solution to the need for ultrafast computation with low power consumption. Several key mathematical operations, including spatial derivatives for edge detection, have recently been demonstrated. However, these initial approaches are typically characterized by a small numerical aperture (NA), strong polarization dependence, narrow operational bandwidths, or the need for complex nanofabrication procedures. Here, we demonstrate how a very simple 7-layer thin-film stack provides dual-channel, high efficiency, polarization-independent 2D edge detection with a numerical aperture approaching 0.9, by leveraging the intrinsic properties of Tamm plasmon polariton resonances. By engineering the resonant decay rates, we propose simple design rules for the layer stack to achieve high-efficiency edge detection with a NA that matches the desired spatial resolution. Using this, we experimentally demonstrate edge detection of micrometer-scale targets with a bandwidth reaching up to 10 nm, enabling operation under filtered, unpolarized, and low-coherence illumination from a halogen lamp. Our results push optical image edge detection toward a wider range of practical applications, including high-resolution microscopy.