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Published February 14, 2018 | Supplemental Material + Submitted
Journal Article Open

Electronically Tunable Perfect Absorption in Graphene


The demand for dynamically tunable light modulation in flat optics applications has grown in recent years. Graphene nanostructures have been extensively studied as means of creating large effective index tunability, motivated by theoretical predictions of the potential for unity absorption in resonantly excited graphene nanostructures. However, the poor radiative coupling to graphene plasmonic nanoresonators and low graphene carrier mobilities from imperfections in processed graphene samples have led to low modulation depths in experimental attempts at creating tunable absorption in graphene devices. Here we demonstrate electronically tunable perfect absorption in graphene, covering less than 10% of the surface area, by incorporating multiscale nanophotonic structures composed of a low-permittivity substrate and subwavelength noble metal plasmonic antennas to enhance the radiative coupling to deep subwavelength graphene nanoresonators. To design the structures, we devised a graphical method based on effective surface admittance, elucidating the origin of perfect absorption arising from critical coupling between radiation and graphene plasmonic modes. Experimental measurements reveal 96.9% absorption in the graphene plasmonic nanostructure at 1389 cm–1, with an on/off modulation efficiency of 95.9% in reflection.

Additional Information

© 2018 American Chemical Society. Received: October 14, 2017; Revised: January 3, 2018; Published: January 10, 2018. This work was supported by US Department of Energy (DOE) Office of Science Grant DE-FG02-07ER46405 (S.K., K.W.M., L.K., and H.A.A.), by the Multidisciplinary University Research Initiative Grant, Air Force Office of Scientific Research MURI, Grant FA9550-12-1-0488 (V.W.B.), and by the National Research Foundation of Korea (NRF) Grants funded by the Ministry of Science and ICT (2017R1E1A1A01074323, M.S.J) and by the Ministry of Education (2017R1D1A1B03034762, M.S.J). S.K. acknowledges support by a Samsung Scholarship. The authors thank G. Rossman for assistance with the FTIR microscope and W.-H. Lin for assistance with fabrication. Author Contributions: S.K., M.S.J., and V.W.B. contributed equally. S.K. and H.A.A. conceived the ideas. S.K., M.S.J., and K.W.M. performed the simulations and formulated the analytic model. S.K. fabricated the sample. S.K., V.W.B., K.W.M., and L.K. performed measurements and data analysis. All authors cowrote the paper, and H.A.A. supervised the project. The authors declare no competing financial interest.

Attached Files

Submitted - 1703.03579.pdf

Supplemental Material - nl7b04393_si_001.pdf


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August 19, 2023
October 26, 2023