Dispersive characteristics of surface plasmon polaritons on negative refractive index gratings

2011 ◽  
Vol 284 (22) ◽  
pp. 5242-5247 ◽  
Author(s):  
M. Cuevas ◽  
R.A. Depine
Keyword(s):  
Refractive Index ◽  
Surface Plasmon ◽  
Surface Plasmon Polaritons ◽  
Negative Refractive Index ◽  
Plasmon Polaritons

scholarly journals Surface Enhanced Raman Scattering on Silver sinusoidal nano-grating: Impact of Interactions of grating-coupled Surface Plasmon polaritons

2021 ◽  
Author(s):  
Zhaoyi Chen ◽  
Ke Feng ◽  
Zhibin Chen ◽  
Jinxing Shen ◽  
Huanliang Li
Keyword(s):  
Refractive Index ◽  
Raman Scattering ◽  
Surface Plasmon ◽  
Surface Plasmon Polaritons ◽  
Surface Enhanced Raman Scattering ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Enhanced Raman Scattering ◽  
The Impact ◽  
Plasmon Polaritons

Abstract In this study, we reported a silver sinusoidal nanograting used in microchannels, forming H2O/Ag/NOA heterostructure, and studied the impact of interactions of grating-coupled surface Plasmon polaritons (SPPs) on Surface-enhanced Raman Scattering (SERS). FDTD simulations showed that when the refractive index of NOA is close to that of H2O, there were two modes of odd coupling and even coupling between SPPs. Additionally, the thinner the Ag grating, the stronger the coupling, accompanied by the frequency shift of the two coupling modes. We also estimated the influence of refractive index of the surrounding medium on SPPs coupling by varying the dielectric of the upper and lower layer of Ag grating. Our experimental results were supported by FDTD calculations, which confirmed the importance of the interactions of grating-coupled SPPs in the design of SERS substrate.

scholarly journals High Sensitive Biosensors Based on the Coupling Between Surface Plasmon Polaritons on Titanium Nitride and a Planar Waveguide Mode

Sensors ◽  
2020 ◽  
Vol 20 (6) ◽  
pp. 1784 ◽  
Author(s):  
Junior Asencios ◽  
Ramiro Moro ◽  
Clemente Luyo ◽  
Arturo Talledo
Keyword(s):  
Refractive Index ◽  
Absorption Band ◽  
Titanium Nitride ◽  
Surface Plasmon ◽  
Surface Plasmon Polaritons ◽  
Planar Waveguide ◽  
Waveguide Mode ◽  
Fano Resonances ◽  
Broad Absorption Band ◽  
Plasmon Polaritons

High sensitivity biosensors based on the coupling of surface plasmon polaritons on titanium nitride (TiN) and a planar waveguide mode were built; they were proved by sensing three different media: air, water and dried egg white; sensors described here could be useful for sensing materials with a refractive index between 1.0 and 1.6; in particular, materials of biological interest with a refractive index in the range 1.3–1.6, like those containing biotin and/or streptavidin. They were built by depositing Nb2O5/SiO2/TiN multilayer structures on the flat surface of D-shaped sapphire prisms by using the dc magnetron sputtering technique. Attenuated total reflection (ATR) experiments in the Kretschmann configuration were accomplished for the air/TiN/Prism and S/Nb2O5/SiO2/TiN/Prism structures, S being the sample or sensing medium. ATR spectra for plasmons at the TiN/air interface showed a broad absorption band for angles of incidence between 36 and 85°, with full width at half maximum (FWHM) of approximately 40°. For the S/Nb2O5/SiO2/TiN/Prism structures, ATR spectra showed a sharp reflectivity peak, within the broad plasmonic absorption band, which was associated with Fano resonances. The angular position and FWHM of the Fano resonances strongly depend on the refractive index of the sensing medium. ATR spectra were fitted by using the transfer-matrix method. Additionally, we found that angular sensitivity and figure of merit increase with increasing the refractive index of the sensing medium.

Identification of Fluids by the Color of Surface Plasmon Polaritons

2014 ◽  
Vol 625 ◽  
pp. 316-321
Author(s):  
Miyu Ozaki ◽  
Tomohisa Sakai ◽  
Hiromichi Murata ◽  
Ryoshu Furutani
Keyword(s):  
Refractive Index ◽  
Surface Plasmon ◽  
Surface Plasmon Polaritons ◽  
White Light ◽  
Low Cost ◽  
High Sensitivity ◽  
Light Illumination ◽  
Label Free ◽  
Free Electrons ◽  
Plasmon Polaritons

When optical waves make the free electrons on a metal surface resonate, optical energy propagates along the surface as density waves of the free electrons. The longitudinal waves and electrical fields of the electrons are called surface plasmon polaritons (SPPs), which are widely applied in high sensitivity sensors because the excitation of SPPs sensitively depends on the refractive index of the surrounding dielectric sample. Here, we report the identification of fluids by using the color dispersion of SPPs. Silver film on a prism surface is illuminated with white light to excite SPPs. A color component in the white light is thereby selectively coupled with SPPs due to the color dispersion that depends on the refractive index of the fluid on the film. Thus, theoretically, when the refractive index is changed, the color of SPPs changes as well. Our application uses a medium consisting of fluid samples to be identified. The proposed identification method can be applied to fluid analysis for label-free visualization of or as a simple analysis method, since the refractive indices or concentrations of the sample fluids directly affect the color of the SPPs, and this color can be visually identified. We theoretically confirmed that the color of SPPs excited with white light illumination can help to differentiate between water and ethanol. Experimentally, SPPs belonging to the frequency region of the color green were detected when the sample was water, and the color changed to red when ethanol was used instead. In the future, we plan to develop simple, small, sensitive, and low-cost sensors that can determine the concentration and refractive index of fluids on the basis of the color of the SPPs.

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