Emulating Nonmagnetic Faraday Rotation with Time-Modulated Metasurface

We propose a nonmagnetic cascaded structure comprising a two-layer time-modulated nonreciprocal metasurface and a 45° polarization grating that can emulate the Faraday rotation effect. Through precise time modulation, the architecture achieves independent control of nonreciprocal transmission intensity and directionality for both x- and y-polarized waves. The polarization-selective grating filters the 45° polarized component to ensure signal purity, thereby effectively simulating the Faraday rotation characteristics. Numerical simulations on the realistic design agree with theoretical predictions, validating the proposed spatiotemporal modulation mechanism. Notably, this work establishes a novel paradigm for realizing Faraday rotation through time-modulated method, offering distinct advantages over conventional magneto-optical approaches.