Ultracompact Amplitude Modulator by Coupling Hyperbolic Polaritons over a Graphene-Covered Gap

Matthias Maier, Andrei Nemilentsau, Tony Low, Mitchell Luskin

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

The hyperbolic phonon-polaritons within the Reststrahlen band of hBN are of great interest for applications in nanophotonics, as they are capable of propagating light signals with low losses over large distances. However, due to the phononic nature of the polaritons in hBN, amplitude modulation of its signal proves to be difficult and has been underexplored. In this paper, we propose theoretically a broadband efficient amplitude modulator for hyperbolic rays in hBN operating in the frequency range between 1450 and 1550 cm-1. The modulating region comprises a few tens of nanometers wide gap carved within the hBN slab and covered by a graphene layer, where electrostatically gated graphene serves as a mediator that facilitates the coupling between phonon-polaritons on each side of the gap through plasmonic modes within graphene. We demonstrate that such an ultracompact modulator has insertion losses as low as 3 dB and provides modulation depth varying between 14 and 20 dB within the type-II hyperbolicity region of hBN.

Original languageEnglish (US)
Pages (from-to)544-551
Number of pages8
JournalACS Photonics
Volume5
Issue number2
DOIs
StatePublished - Feb 21 2018

Bibliographical note

Funding Information:
M.M., A.N., T.L., and M.L. have been partially supported by the Army Research Office (ARO) Multidisciplinary University Research Initiative (MURI) Award No. W911NF-14-1-0247.

Keywords

  • graphene
  • hBN
  • hyperbolic rays
  • modulator
  • plasmons

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