Plasmonic computing of spatial differentiation

TLDR

Optical analog computing offers high‑throughput, low‑power computation, yet conventional spatial‑domain implementations rely on bulky lenses and filters, and although metamaterials enable sub‑wavelength miniaturization, the complex meta‑atom arrays still hinder direct image‑processing demonstrations. The study aims to show that surface‑plasmon interference at a single metal–dielectric interface can perform spatial differentiation. This is achieved by exploiting the interference of surface plasmons excited at the interface, enabling spatial differentiation without bulky optics. Experimentally, the authors demonstrate edge detection of an image without any Fourier lens, revealing a simple, powerful nanoscale optical analog computing mechanism.

Abstract

Abstract Optical analog computing offers high-throughput low-power-consumption operation for specialized computational tasks. Traditionally, optical analog computing in the spatial domain uses a bulky system of lenses and filters. Recent developments in metamaterials enable the miniaturization of such computing elements down to a subwavelength scale. However, the required metamaterial consists of a complex array of meta-atoms, and direct demonstration of image processing is challenging. Here, we show that the interference effects associated with surface plasmon excitations at a single metal–dielectric interface can perform spatial differentiation. And we experimentally demonstrate edge detection of an image without any Fourier lens. This work points to a simple yet powerful mechanism for optical analog computing at the nanoscale.