Metallic Nanodisk-in-Elliptical Nanohole Array Based Fiber Tip for Enhanced Plasmonic Refractometric Sensing

In this work, a high performance surface plasmon resonance (SPR) fiber sensor based on metallic elliptical nanohole and circular nanodisk binary array has been theoretically designed and investigated. The binary array structure is integrated on the end facet of optical fiber to excite SPR and generate three optical resonance dips in reflection spectra in the near-infrared region. The first resonance dip not only fits the characteristics of narrow linewidth, but also has the advantages of high peak-to-dip signal ratio and sensitivity. When the external environment changes in the refractive index (RI) range of 1.33 similar to 1.40, a high RI sensitivity of 669 nm/RIU, a narrow FWHM of 5.8 nm, and a high FOM value of 115.3 are yielded simultaneously for the first dip. Compared to unitary nanostructure arrays, the composite plasmonic structure of nanodisk and elliptical nanohole array demonstrated here can generate SPR modes with sharper spectral feature which is crucial to high sensitivity and precision detection technology. These features make our proposed plasmonic fiber tip sensor highly promising in terms of high-performance biosensing applications.

Automated summary

A high performance surface plasmon resonance (SPR) fiber sensor based on metallic elliptical nanohole and circular nanodisk binary array is designed and investigated in this work. The binary array structure integrated on the end facet of optical fiber can generate three optical resonance dips in the near-infrared region. The first dip shows narrow linewidth, high peak-to-dip signal ratio, and sensitivity. The sensor exhibits high refractive index (RI) sensitivity, narrow FWHM, and high FOM value simultaneously. The composite plasmonic structure of nanodisk and elliptical nanohole array can generate SPR modes with sharper spectral feature, which is crucial for high sensitivity and precision detection technology.