Li J, Zhang Z, Xu G, Sun H, Dai L, Li T, Qiu CW. Tunable Rectification of Diffusion-Wave Fields by Spatiotemporal Metamaterials.
PHYSICAL REVIEW LETTERS 2022;
129:256601. [PMID:
36608240 DOI:
10.1103/physrevlett.129.256601]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
The diffusion process is the basis of many branches of science and engineering, and generally obeys reciprocity between two ports of a linear time-invariant medium. Recent research on classical wave dynamics has explored the spatiotemporal modulation to exhibit preferred directions in photons and plasmons. Here we report a distinct rectification effect on diffusion-wave fields by modulating the conductivity and observe nonreciprocal transport of charges. We experimentally create a spatiotemporal diffusion metamaterial, in which a mode transition to zero frequency is realized. A direct current component thereby emerges, showcasing a biased effect on the charge diffusion when the incident fundamental frequency is a multiple of the system modulation frequency. These results may find applications spanning a plethora of diffusive fields in general.
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