Cascaded wavelength multiplexed refractive index sensors in optical fibers based on surface plasmon resonances

We investigate Fano resonances and sensing enhancements in a simple Au/TiO2 hybrid metasurface through the finite-different time-domain (FDTD) simulation and coupled mode theory (CMT) analysis. The results show that the Fano resonance in the proposed simple metasurface is caused by the destructive interaction between the surface plasmon polaritons (SPPs) and the local surface plasmon resonances (LSPRs), the quality factor and dephasing time for the Fano resonance can be effectively tuned by the thickness of Au and TiO2 structures, the length of each unit in x and y directions, as well as the structural defect. In particular, single Fano resonance splits into multiple Fano resonances caused by a stub-shaped defect, and multiple Fano resonances can be tuned by the size and position of the stub-shaped defect. Moreover, we also find that the sensitivity in the Au/TiO2 hybrid metasurface with the stub-shaped defect can reach up to 330 nm/RIU and 535 nm/RIU at the Fano resonance 1 and Fano resonance 2, which is more than three times as sensitive in the Au/TiO2 hybrid metasurface without the stub-shaped defect, and also higher than that in the TiO2 metasurface reported before. These results may provide further understanding of Fano resonances and guidance for designing ultra-high sensitive refractive index sensors.

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Surface Plasmon Resonances in Sierpinski-Like Photonic Crystal Fibers: Polarization Filters and Sensing Applications

Molecules ◽

10.3390/molecules25204654 ◽

2020 ◽

Vol 25 (20) ◽

pp. 4654

Author(s):

William O. F. Carvalho ◽

J. R. Mejía-Salazar

Keyword(s):

Refractive Index ◽

Photonic Crystal ◽

Surface Plasmon ◽

Wavelength Range ◽

Circular Cross Section ◽

Wide Band ◽

Surface Plasmon Resonances ◽

Refractive Index Sensing ◽

Sensing Applications ◽

Plasmon Resonances

We investigate the plasmonic behavior of a fractal photonic crystal fiber, with Sierpinski-like circular cross-section, and its potential applications for refractive index sensing and multiband polarization filters. Numerical results were obtained using the finite element method through the commercial software COMSOL Multiphysics®. A set of 34 surface plasmon resonances was identified in the wavelength range from λ=630 nm to λ=1700 nm. Subsets of close resonances were noted as a consequence of similar symmetries of the surface plasmon resonance (SPR) modes. Polarization filtering capabilities are numerically shown in the telecommunication windows from the O-band to the L-band. In the case of refractive index sensing, we used the wavelength interrogation method in the wavelength range from λ=670 nm to λ=790 nm, where the system exhibited a sensitivity of S(λ)=1951.43 nm/RIU (refractive index unit). Due to the broadband capabilities of our concept, we expect that it will be useful to develop future ultra-wide band optical communication infrastructures, which are urgent to meet the ever-increasing demand for bandwidth-hungry devices.

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Surface Plasmon Resonances in Oriented Silver Nanowire Coatings on Optical Fibers

The Journal of Physical Chemistry C ◽

10.1021/jp5025069 ◽

2014 ◽

Vol 118 (20) ◽

pp. 11035-11042 ◽

Cited By ~ 31

Author(s):

Jean-Michel Renoirt ◽

Marc Debliquy ◽

Jacques Albert ◽

Anatoli Ianoul ◽

Christophe Caucheteur

Keyword(s):

Surface Plasmon ◽

Optical Fibers ◽

Silver Nanowire ◽

Surface Plasmon Resonances ◽

Plasmon Resonances

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Refractive Index Sensing of Monolayer Molecules Using Both Local and Propagating Surface Plasmons in Mid-Infrared Metagrating

Applied Sciences ◽

10.3390/app9081524 ◽

2019 ◽

Vol 9 (8) ◽

pp. 1524 ◽

Cited By ~ 2

Author(s):

De He ◽

Tieyan Zhang ◽

Lu Liu ◽

Shixing Guo ◽

Zhijun Liu

Keyword(s):

Refractive Index ◽

Surface Plasmon ◽

Spectral Band ◽

Broad Band ◽

Surface Plasmon Resonances ◽

Molecular Fingerprint ◽

Mid Infrared ◽

Refractive Index Sensing ◽

Metal Insulator Metal ◽

Plasmon Resonances

Surface-enhanced infrared absorption spectroscopy (SEIRA) is attractive for molecular sensing due to its high sensitivity and access to molecular fingerprint absorptions. In this paper, we report on refractive index sensing of monolayer molecules in a spectral band outside the molecular fingerprint region. In a metagrating composed of a three-layer metal-insulator-metal structure, both propagating surface plasmon resonances (PSPs) and local surface plasmon resonances (LSPRs) are exited from free-space in a broad band of 3 to 9 µm, and their sensing properties are characterized. In response to a self-assembled monolayer of octadecanethiol (ODT) molecules, both PSPs and LSPRs exhibit redshifts in wavelength. The shifts of LSPRs are larger than those of PSPs, as originated from their stronger spatial confinement and larger field enhancement. Our proposed mid-infrared molecular sensor is immune to frequency variations of plasmon resonance and more tolerant to sample feature size variation.

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