A single passive terahertz metasurface implementing eight Boolean logic gates through polarization multiplexing

Abstract

Optical logic gates promise computing at the speed of the carrier wave, and metasurfaces provide their most compact platform; yet the gate count on one aperture has grown only by adding diffractive layers, active materials, or coherently controlled input beams. Here we demonstrate eight logic gates on a passive transmissive metasurface at 1 THz: OR, AND, XOR and BUFFER, together with their complements NOR, NAND, XNOR and NOT. A binary spatial mask pre-encodes the gate and input state, so the device is a wavefront-encoded logic mapper; the logical output is whichever detector window collects more energy. Two orthogonal linear polarizations act as parallel processing channels: two phase profiles, trained separately through a Rayleigh–Sommerfeld diffractive model, are carried by one gold-on-polyimide unit cell whose crossed resonant arms tune the x - and y -polarized transmission phases through separate geometric parameters. Under \(45^{\circ }\) linearly polarized illumination, each mask state therefore evaluates a gate and its complement simultaneously. Full-wave simulations confirm correct routing for all 28 gate–input combinations, with a mean detector contrast of 13.22 dB and a minimum of 5.88 dB on a \(16\lambda _0\times 16\lambda _0\) aperture. This polarization-multiplexed strategy raises the functional density of passive wave-based computing.