Highly Sensitive Plasmonic Structures Utilizing a Silicon Dioxide Overlayer

0561882 - ÚPT 2023 RIV CH eng J - Journal Article
Chylek, J. - Maniaková, P. - Hlubina, P. - Sobota, Jaroslav - Pudiš, D.
Highly Sensitive Plasmonic Structures Utilizing a Silicon Dioxide Overlayer.
Nanomaterials. Roč. 12, č. 18 (2022), č. článku 3090. E-ISSN 2079-4991
Institutional support: RVO:68081731
Keywords : surface plasmon resonance * Kretschmann configuration * silicon dioxide overlayer * reflectance * aqueous analyte sensing
OECD category: Optics (including laser optics and quantum optics)
Impact factor: 5.3, year: 2022
Method of publishing: Open access
https://www.mdpi.com/2079-4991/12/18/3090

In this paper, simple and highly sensitive plasmonic structures are analyzed theoretically and experimentally. A structure comprising a glass substrate with a gold layer, two adhesion layers of chromium, and a silicon dioxide overlayer is employed in liquid analyte sensing. The sensing properties of two structures with distinct protective layer thicknesses are derived based on a wavelength interrogation method. Spectral reflectance responses in the Kretschmann configuration with a coupling BK7 prism are presented, using the thicknesses of individual layers obtained by a method of spectral ellipsometry. In the measured spectral reflectance, a pronounced dip is resolved, which is strongly red-shifted as the refractive index (RI) of the analyte increases. Consequently, a sensitivity of 15,785 nm per RI unit (RIU) and a figure of merit (FOM) of 37.9 RIU-1 are reached for the silicon dioxide overlayer thickness of 147.5 nm. These results are in agreement with the theoretical ones, confirming that both the sensitivity and FOM can be enhanced using a thicker silicon dioxide overlayer. The designed structures prove to be advantageous as their durable design ensures the repeatability of measurement and extends their employment compared to regularly used structures for aqueous analyte sensing.
Permanent Link: https://hdl.handle.net/11104/0335270