Tunable Wave Isolators Based on Space-time Modulated Graphene Sheets

Xuchen Wang, Ana Diaz-Rubio, Huanan Li, Andrea Alu

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review


In this talk, we propose a tunable metasurface isolator based on space-time (ST) modulated surface impedance. The surface impedance is synthesized by periodic graphene strips with spatiotemporal gating. General and rigorous analytical formulations are developed to calculate all the scattering harmonics for such modulated metasurfaces. We found that with the space modulation of the graphene impedance, the structure can excite evanescent modes that propagate asymmetrically in space. This spatial asymmetry results in strong nonreciprocal effect under time modulation: the device can reflect waves coming from one angle without frequency conversion, while for the oppositely tilted incidence, waves are fully transformed into evanescent fields and absorbed. We also show that the proposed wave isolator can be tuned and robustly operate in a wide frequency spectrum (5.5 12.1 THz) only by modifying the pumping functions.

Original languageEnglish
Title of host publication2019 PhotonIcs and Electromagnetics Research Symposium - Spring, PIERS-Spring 2019 - Proceedings
Number of pages8
ISBN (Electronic)9781728134031
Publication statusPublished - 1 Jun 2019
MoE publication typeA4 Article in a conference publication
EventProgress in Electromagnetics Research Symposium - Rome, Italy
Duration: 17 Jun 201920 Jun 2019

Publication series

NameProgress in Electromagnetics Research Symposium
ISSN (Print)1559-9450
ISSN (Electronic)1931-7360


ConferenceProgress in Electromagnetics Research Symposium
Abbreviated titlePIERS

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