Complete Complex Amplitude Modulation with Electronically Tunable Graphene Plasmonic Metamolecules

Sangjun Han, Seyoon Kim, Shinho Kim, Tony Low, Victor Watson Brar, Min Seok Jang

Research output: Contribution to journalArticle

1 Scopus citations

Abstract

Dynamic high-resolution wavefront modulation of light is a long-standing quest in photonics. Metasurfaces have shown potential for realizing light manipulation with subwavelength resolution through nanoscale optical elements, or metaatoms, to overcome the limitations of conventional spatial light modulators. State-of-the-art active metasurfaces operate via phase modulation of the metaatoms, and their inability to also independently control the scattered amplitude leads to an inferior reconstruction of the desired wavefronts. This fundamental problem posed severe performance limitations particularly for applications relying on subwavelength spatiotemporal complex field modulation, which includes dynamic holography, high-resolution imaging, optical tweezing, and optical information processing. Here, we present the "metamolecule" strategy, which incorporates two independent subwavelength scatterers composed of noble metal antennas coupled to gate-tunable graphene plasmonic nanoresonators. The two-parametric control of the metamolecule secures the complete control of both amplitude and phase of light, enabling 2πphase shift as well as large amplitude modulation including perfect absorption. We further develop a generalized graphical model to examine the underlying requirements for complete complex amplitude modulation, offering intuitive design guidelines to maximize the tunability in metasurfaces. To illustrate the reconfigurable capability of our designs, we demonstrate dynamic beam steering and holographic wavefront reconstruction in periodically arranged metamolecules.

Original languageEnglish (US)
Pages (from-to)1166-1175
Number of pages10
JournalACS nano
Volume14
Issue number1
DOIs
StatePublished - Jan 28 2020

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Keywords

  • complex amplitude modulation
  • graphene
  • mid-infrared
  • nanoresonator
  • plasmonics

PubMed: MeSH publication types

  • Journal Article

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