Title: Suppression of near-field coupling in plasmonic antennas on epsilon-near-zero substrates

Abstract

Epsilon-near-zero (ENZ) media are an emerging class of nanophotonic materials that engender electromagnetic fields with small phase variation due to their approximately zero permittivity. These quasi-static fields facilitate several unique optical properties, such as subwavelength confinement, arbitrary wavefront control, and enhanced light–matter interactions, which make ENZ materials promising platforms for nanophotonic and plasmonic systems. Here, we report our analysis of single and dimer nanoantennas deposited on an aluminum-doped zinc oxide layer with an ENZ wavelength around 1.5 μm. Using near-field microscopy, far-field spectroscopy, finite-element numerical simulations, and a semi-analytic Fabry–Perot (FP) model, we show that single nanoantennas support highly dispersive plasmonic modes with less than unity effective mode index at wavelengths greater than the ENZ wavelength, which consequently fixes the resonance near the ENZ wavelength of the substrate. Furthermore, we observe a strong reduction in the near-field coupling between dimer nanoantennas via measurements of the resonance shift as a function of gap size. This reduction of near-field coupling allows one to design arrays of independently operating antennas with higher densities and thereby significantly improve the array characteristics, especially when targeting gradient metasurface implementations. Our results demonstrate the use of ENZ materials for increasing the versatility and functionality of plasmonic structuresmore » and provide foundational insight into this exotic material phenomenon.« less

Authors:

DeVault, Clayton T.; Zenin, Vladimir A. ;

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Pors, Anders; Chaudhuri, Krishnakali; Kim, Jongbum; Boltasseva, Alexandra; Shalaev, Vladimir M.; Bozhevolnyi, Sergey I.

Publication Date:

2018-12-04

Research Org.:

Purdue Univ., West Lafayette, IN (United States)

Sponsoring Org.:

USDOE Office of Science (SC)

OSTI Identifier:

1484318

Alternate Identifier(s):

OSTI ID: 1612749

Grant/Contract Number:  

SC0017717

Resource Type:

Journal Article: Published Article

Journal Name:

Optica

Additional Journal Information:

Journal Name: Optica Journal Volume: 5 Journal Issue: 12; Journal ID: ISSN 2334-2536

Publisher:

Optical Society of America

Country of Publication:

United States

Language:

English

Subject:

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; Optics