Tuning the optical response of a plasmonic T-shaped dimer with nanowire loads for improved SERS and sensing applications

Plasmonic nanostructures have important applications for surface-enhanced Raman chips, optical sensors, perfect absorbers, and so on. In this paper, we theoretically investigate the optical properties of a T-shaped dimer (TD) nanostructure and a TD with nanowire loads (TD/NL) nanostructure. By depos...

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Bibliographic Details
Published inJournal of physics. D, Applied physics Vol. 54; no. 8; pp. 84001 - 84009
Main Authors Ren, Mengke, Li, Ran, Wang, Junqiao, Fan, Chunzhen, Ding, Pei, Li, Yan, He, Jinna
Format Journal Article
LanguageEnglish
Published IOP Publishing 25.02.2021
Subjects
Fano resonance
sensor
SERS
surface plasmon
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Summary:Plasmonic nanostructures have important applications for surface-enhanced Raman chips, optical sensors, perfect absorbers, and so on. In this paper, we theoretically investigate the optical properties of a T-shaped dimer (TD) nanostructure and a TD with nanowire loads (TD/NL) nanostructure. By depositing the NLs around the TD, the optical property of the TD is significantly modified, and the extinction spectrum of composite TD/NL appears the splitting resonance peak and shows the asymmetric characteristic of Fano resonance due to the plasmon hybridization. Besides, a stronger electric field enhancement can be obtained in the composite TD/NL nanostructure, and the calculated results show the field enhancement effect of the dark mode in designed TD/NL nanostructure is three times than that in the TD nanostructure. Furthermore, the Fano resonance in TD/NL nanostructure reveals the narrow spectral linewidth and high quality factor, which is advantageous to optical refractive index sensors, and the corresponding sensing sensitivity is as high as 1083 nm RIU−1.
Bibliography:JPhysD-125383.R1
ISSN:0022-3727
1361-6463
DOI:10.1088/1361-6463/abc6d8