title: Experimental Demonstration of Phase Modulation and Motion Sensing Using Graphene-Integrated Metasurfaces.
abstract: Strong interaction of graphene with light accounts for one of its most remarkable properties: the ability to absorb 2.3% of the incident light's energy within a single atomic layer. Free carrier injection via field-effect gating can dramatically vary the optical properties of graphene, thereby enabling fast graphene-based modulators of the light intensity. However, the very thinness of graphene makes it difficult to modulate the other fundamental property of the light wave: its optical phase. Here we demonstrate that considerable phase control can be achieved by integrating a single-layer graphene (SLG) with a resonant plasmonic metasurface that contains nanoscale gaps. By concentrating the light intensity inside of the nanogaps, the metasurface dramatically increases the coupling of light to the SLG and enables control of the phase of the reflected mid-infrared light by as much as 55° via field-effect gating. We experimentally demonstrate graphene-based phase modulators that maintain the amplitude of the reflected light essentially constant over most of the phase tuning range. Rapid nonmechanical phase modulation enables a new experimental technique, graphene-based laser interferometry, which we use to demonstrate motion detection with nanoscale precision. We also demonstrate that by the judicious choice of a strongly anisotropic metasurface the graphene-controlled phase shift of light can be rendered polarization-dependent. Using the experimentally measured phases for the two orthogonal polarizations, we demonstrate that the polarization state of the reflected light can be by modulated by carrier injection into the SLG. These results pave the way for novel high-speed graphene-based optical devices and sensors such as polarimeters, ellipsometers, and frequency modulators.
authors.forename: Nima
authors.initials: N
authors.lastname: Dabidian
authors.forename: Shourya
authors.initials: S
authors.lastname: Dutta-Gupta
authors.affiliation: CNR-INO, Sensor Lab, The University of Brescia , via Branze 45, 25123, Brescia, Italy.
authors.forename: Iskandar
authors.initials: I
authors.lastname: Kholmanov
authors.forename: Kueifu
authors.initials: K
authors.lastname: Lai
authors.affiliation: Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin , 10100 Burnet Road, Austin, Texas 78758, United States.
authors.forename: Feng
authors.initials: F
authors.lastname: Lu
authors.affiliation: Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin , 10100 Burnet Road, Austin, Texas 78758, United States.
authors.forename: Jongwon
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin , 10100 Burnet Road, Austin, Texas 78758, United States.
authors.forename: Mingzhou
authors.initials: M
authors.lastname: Jin
authors.forename: Simeon
authors.initials: S
authors.lastname: Trendafilov
authors.affiliation: Department of Physics, Queens College of The City University of New York , Queens, New York 11367, United States.|The Graduate Center of The City University of New York , New York, New York10016, United States.
authors.forename: Alexander
authors.initials: A
authors.lastname: Khanikaev
authors.affiliation: Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin , 10100 Burnet Road, Austin, Texas 78758, United States.
authors.forename: Babak
authors.initials: B
authors.lastname: Fallahazad
authors.affiliation: Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin , 10100 Burnet Road, Austin, Texas 78758, United States.
authors.forename: Emanuel
authors.initials: E
authors.lastname: Tutuc
authors.affiliation: Department of Electrical and Computer Engineering, Microelectronics Research Center, The University of Texas at Austin , 10100 Burnet Road, Austin, Texas 78758, United States.
authors.forename: Mikhail A
authors.initials: MA
authors.lastname: Belkin
authors.forename: Gennady
authors.initials: G
authors.lastname: Shvets
keywords: Fano resonance; Plasmonic metasurfaces; graphene; mid-infrared; phase modulation; polarization modulation