Nanoimprint lithography-based fabrication of plasmonic array of elliptical nanoholes for dual-wavelength, dual-polarisation refractive index sensing
Robinson, Caoimhe; Justice, John; Petäjä, Jarno; Karppinen, Mikko; Corbett, Brian M.; O'Riordan, Alan; Lovera, Pierre
Date:
2018-11-10
Copyright:
© 2018, Springer Science+Business Media, LLC, part of Springer Nature. All rights reserved. The final publication is available at Springer via https://doi.org/10.1007/s11468-018-0879-z
Full text restriction information:
Access to this article is restricted until 12 months after publication by request of the publisher.
Restriction lift date:
2019-11-10
Citation:
Robinson, C., Justice, J., Petäjä, J., Karppinen, M.,Corbett, B., O'Riordan, A. and Lovera, P. (2018) 'Nanoimprint lithography-based fabrication of plasmonic array of elliptical nanoholes for dual-wavelength, dual-polarisation refractive index sensing', Plasmonics. doi:10.1007/s11468-018-0879-z
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.
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