Surface plasmon resonance wave coupling

Byun KM, Kim SJ, Kim D (2005) Design study of highly sensitive nanowire-enhanced surface plasmon resonance biosensors using rigorous coupled wave analysis. Opt Express 13 3737-3742... 

Modified fiber-optic-based sensors can be used for sensing pollutants, explosives, drugs, pharmaceuticals, and miscellaneous organics (Yeh et al. 2006). Optical fibers coated with porous silica can be used to detect the presence of chlorinated hydrocarbons. Alternatively, these compounds can also be detected using fiber-optic-coupled surface plasmon resonance methods. Aromatic compounds were detected by evanescent wave absorption spectroscopy. Suitably modified fiber-optic array tips can be used to detect presence of explosive materials (Wolfbeis 2000). 

FIGURE 21-14 Surface plasmon resonance. Laser radiation is coupled into the glass substrate coaled with a thin metal film by a half-cylindrical prism. If total internal reflection occurs, an evanescent wave is generated in the medium of lower refractive index. This wave can exciie surface plasmon waves. When the angle Is suitable for surface plasmon resonance, a sharp decrease in the reflected intensity is observed at the detector. 

In principle, there is a close analogy between QCM and surface plasmon resonance (SPR) spectroscopy. Both types of resonators couple to the environment by rapidly deca3dng waves, and the... 

As the simplest nanoantennas, plasmonic nanoparticles can be utilized to enhance the absorption within thin-film solar cells [243]. They couple incoming waves with the localized SPP field, have increased scattering cross-section and strongly localize electromagnetic field just in the thin active region of the detector. Fig. 2.62. The same principle is applicable for infrared detection [321]. This cannot be done with pure noble metal nanoparticles since their surface plasmon resonance is in ultraviolet or visible part of the spectrum. Because of that their response must be redshifted. In this part, two approaches to such redshifting are described. 

In the previous sections we have considered electromagnetic waves which propagate in an homogeneous material or which are reflected at an interface. A different type of electromagnetic waves which are important in metal optics are the delocalized surface plasmon resonances or surface plasmon polaritons (SPPs), which consist in propagating, dispersive electromagnetic waves coupled to the electron plasma of a metal at a dielectric interface, but evanescently confined in the perpendicular direction [7,12,13]. 

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