Photon-Blockade Analogue Nonreciprocal Absorption in Spatiotemporal Metasurfaces

TL;DR

This paper demonstrates a superconducting metasurface that achieves nonreciprocal absorption akin to photon blockade, enabling one-way energy flow control for quantum and microwave photonics applications.

Contribution

It introduces a spatiotemporally modulated superconducting metasurface with classical wave interference effects mimicking quantum photon blockade, including design and simulation analysis.

Findings

Achieves one-way nonreciprocal absorption at microwave frequencies

Demonstrates strong nonreciprocal behavior via Floquet harmonics

Provides design and simulation framework for superconducting nonreciprocal devices

Abstract

Controlling the flow of electromagnetic energy is essential for advancing quantum technologies. We introduce a spatiotemporally modulated superconducting metasurface that exhibits photon-blockade-analogue nonreciprocal absorption. In this system, the frequency of incident radiation is matched to the modulation frequency of the metasurface, enabling one-way directional absorption. Forward-traveling waves undergo resonant coupling to higher-order Floquet harmonics and are absorbed within the slab, while backward-traveling waves transmit freely without interaction. This behavior arises from classical wave interference and harmonic conversion in a space-time periodic medium, a classical analogue of quantum photon blockade. We present a design based on a superconductor-semiconductor metasurface incorporating cascaded Josephson field-effect transistors (JoFETs) for millikelvin-temperature operation. Our analysis includes the system Hamiltonian, Floquet band structure, isofrequency diagrams, and full-wave simulations demonstrating strong nonreciprocal absorption. These findings establish a pathway toward compact, nonreciprocal superconducting devices for quantum information processing and microwave photonics.