Low-cost, high performance surface plasmon resonance-compatible films characterized by the surface plasmon resonance technique

Abstract

A new analytical method based on the surface plasmon resonance (SPR) technique is presented, with which SPR curves for both wavelength and angular modulations can be obtained simultaneously via only a single scan of the incident angle. Using this method, the SPR responses of TiO2-coated Cu films are characterized in the wavelength range from 600 nm to 900 nm. For the first time, we determine the effective optical constants and the thicknesses of TiO2-coated Cu films using the SPR curves of wavelength modulation. The sensitivities of prism-based SPR refractive index sensors using TiO2-coated Cu films are investigated theoretically for both wavelength and angular modulations, the results show that in the case of sensitivity with wavelength modulation, TiO2-coated Cu films are not as good as the Au film, however, they are more suitable than the Au film for SPR refractive index sensors with angular modulation because a higher sensitivity can be achieved.

Performance evaluation of a bilayer SPR-based fiber optic RI sensor with TiO2 using FDTD solutions

“…This is because silver has the largest |ε r /ε i | ratio, where ε r and ε i define the real and imaginary parts of the permittivity, which account for the reflection and absorption of light in the metal, respectively [1,2]. However, several researchers prefer to use gold because of its chemical stability against oxidation [3,4]. Zynio et al proposed a new structure based on bimetallic layers of Ag and Au on the prism-based configuration where Au was utilized as the outer layer [5].…”

“…Recently, the performance of a prism-based SPR RI sensor coated with copper (Cu)/TiO 2 was investigated theoretically and compared to that coated with Au film only in angular and wavelength interrogation [10]. The implementation of optical fiber based-SPR sensors using Cu and oxides bilayers was reported in [4].…”