Metallic film optimization in a surface plasmon resonance biosensor by the extended Rouard method

Abstract

The extended Rouard method is applied to the computation of a multi-absorbing-layer system for the optimization of surface plasmon resonance (SPR) sensors. Specifically, the effect of the properties of a metallic layer on the shape of the reflectivity and sensitivity curve is demonstrated in the case of a Kretschmann configuration. This theoretical investigation allows us to establish the best optical properties of the metal to obtain a localized SPR, given the illuminating beam properties. Toward the development of a sensitive biosensor based on SPR, we quantify the changes in reflectivity of such an optical biosensor induced by the deposition of a nanometric biochemical film as a function of the metal film characteristics and the illumination operating conditions. The sensitivity of the system emphasizes the potential of such biophotonic technology using metallic multilayer configurations, especially with envisioned metamaterials.

Reflectivity optimization of the SPR graphene sensor

“…It defi nes the maximum dynamic and shape of the plasmon [7,33]. Figure 2 shows the calculated results as a series of SPR curves for silver thickness increasing in steps of 10 nm changing from 10 nm to 100 nm.…”

“…Furthermore, it was found that the variation in metal thickness decreases the amplitude of the resonance peak, which means a reduction in the transfer of incident energy to surface plasmons. The optimization of the thickness of the metal is important to work in the best coupling conditions and have the best sensitivity of the SPR sensor [7,33].…”

“…The noble metals [7,8] as Ag and Au are more commonly used to support the propagation of surface plasmon polariton waves (SPP) at visible light wavelengths [4,9,10]. How-ever, silver substrates seems to be the most appealing, because it provides in the metal-sensing layer interface a high value of electric fi eld enhancement with low imaginary part of refractive index [11].…”

Sensitivity‐enhancement methods for surface plasmon sensors

“…As a result, a much better resolution and higher-precision sensor can be produced by using the double-layer arrangement in comparison to the single-layer profile. The influence of using double metallic film on the sensitivity and stability of the sensor was also investigated by Lecaruyer and coworkers [49]. Since silver, and similarly gold, has poor adherence with glass; therefore chromium or titanium must be inserted to fix the silver or gold layer to the glass substrate.…”

Plasmonic DNA: Towards Genetic Diagnosis Chips

“…The reflectivity minimum that can be reached depends on the thickness of the metal layer [54]. It is a compromise between the penetration depth of the optical wave and the excitation of the surface plasmons.…”