Nanoimprint Lithography–Based Fabrication of Plasmonic Array of Elliptical Nanoholes for Dual-Wavelength, Dual-Polarisation Refractive Index Sensing

Caoimhe Robinson, John Justice, Jarno Petäjä, Mikko Karppinen, Brian Corbett, Alan O’Riordan, Pierre Lovera

Research output: Contribution to journalArticleScientificpeer-review

3 Citations (Scopus)

Abstract

We report on the novel fabrication and characterisation of plasmonic arrays of elliptical nanohole, and their use for refractive index based sensing. The substrates were fabricated using nanoimprint lithography into a chromium hard mask followed by transfer of the patterns into the underlying gold layer by dry etching—a combination of processes amendable to mass manufacturing. 3D-FDTD simulations were undertaken and showed the transmission spectrum was dependant upon the polarisation of the incident light, with a series of minima that can be attributed to plasmonic effects on the gold/water or gold/substrate interfaces. Each polarisation showed two peaks on the gold/water interface, one in the visible and one in the near-infrared part of the spectrum. Simulated electric field profiles showed that the electric field in the infrared propagates deep in the bulk while the one in the visible was more tightly bound to the surface. Experimental transmission spectra of the fabricated samples showed good agreement with the simulated ones. Bulk refractive index experiments were carried out and sensitivities of 293 nm/RIU and 414 nm/RIU were obtained for the two spectral features of interest when the polarisation was along the long axis of the elliptical nanohole for the visible and infrared features, respectively, and 293 nm/RIU and 323 nm/RIU measured when the polarisation was along the short axis of the nanohole.

Original languageEnglish
Pages (from-to)951-959
Number of pages9
JournalPlasmonics
Volume14
Issue number4
Early online date10 Nov 2018
DOIs
Publication statusPublished - 15 Aug 2019
MoE publication typeNot Eligible

Keywords

  • Elliptical
  • Nanohole array
  • Nanoimprint
  • Plasmonics
  • Polarisation
  • OtaNano

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