Electrically tunable metasurface by using InAs in a metal-insulator-metal configuration

Junghyun Park, Seong Jun Kim, Volker J. Sorger, Soo Jin Kim

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

The ability of modulating optical properties at a lateral subwavelength scale is of crucial importance due to its potential applications for wide-angle holographic displays, optical communications, and interferometric sensors. Here, we present an electrically tunable metasurface whose optical properties can be element-wise controlled at the lateral subwavelength scale in the mid-infrared wavelength regime. Our proposed device facilitates an n-doped InAs layer as a dynamic-tunable layer, and the charge carrier concentration inside the InAs layer is tailored by external gate biases. This InAs active layer is sandwiched between top aluminum strip antennas and a bottom gold substrate, forming the metal-insulator-metal configuration. The change of the charge carrier concentration gives rise to modulation of the amplitude and phase of reflected light in a mid-infrared regime. Numerical investigations show the reflectivity contrast of 44%P with biases of -2.5-0 V and the phase change of 236° with biases of -15 V to +15 V at the wavelength of ∼5 μm. Versatile wavefront shaping such as beam focusing with Fresnel Zone plate and beam steering with saw-tooth phase grating is also provided.

Original languageEnglish
Pages (from-to)1117-1126
Number of pages10
JournalNanophotonics
Volume11
Issue number6
DOIs
Publication statusPublished - 2022 Feb 2

Keywords

  • InAs
  • metasurface
  • optical modulator
  • surface plasmonics
  • wavefront shaping

ASJC Scopus subject areas

  • Biotechnology
  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering

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