Yüzey plazmon rezonans sensörleri teorisi ve uygulamaları

In this thesis, electromagnetic theory of surface plasmon resonance (SPR) phenomenon and its applications in optical sensing are investigated. Operation of an SPR sensor is based on the excitation of surface plasmon waves (SPWs) at an interface between two different media, a metal layer and a dielectric layer, with real parts of permittivity having opposite signs. Presence of the SPR shows itself with a sharp minimum in the reflection curve of the sensor that is operated by either the angular interrogation approach or the wavelength interrogation approach. Location of the minimum SPR reflection is highly sensitive to variations in relative permittivity and thickness parameters of the material layers. Even small changes in any one of these parameters can be accurately sensed by measuring the corresponding shift in the location of the minimum point of the SPR reflection curve. Using the prism based coupling method for the excitation of SPWs, the three-layer SPR sensor structure composed of the prism, the thin metal film and the bulk dielectric layer is investigated by both analytical solutions and numerical simulations. Dielectric function models of different metals which are widely used in SPR sensors are included in the analyses to compare the performances of resulting sensor designs. Feasibility of multi-purpose sensing with the same SPR topology is also investigated via numerical CST simulations by using multi-section receptor patches in the sensing dielectric layer to detect the presence of different types of test targets in a given sample solution.