In the current work, the sensitivity of Plasmonic Nanobiosensors based on Plasmonexciton amplification was investigated. Surface Plasmon amplification is the mass movement of free electrons in the metal stimulated by light radiation. If the frequency of the emitted light is equal to the natural frequency of the free electrons of the metal, the surface Plasmon resonance phenomenon occurs, which leads to the coupling between the metal core and the shell, which is the aim of the current work.
For this purpose, several different structures which are able to excite Plasmonic modes and coupling between these modes were initially designed and modelled. To model the interaction of light with the desired structures with different materials, the finite time difference method was used. Considering different materials, the finite time difference (FDTD) method used to model the interaction of light with the nano-structures. The perfect matched layers were considered around the structure and a plane wave in the wavelength range of 300-700 nm is reflected into the structure. To obtain the scatter and cross-sectional area, Suitable detectors were placed around the structure and Drude-Lorentz model was used to describe the optical properties of Plasmonic metals (Gold and Silver) and the pigment molecules. Finally, by changing parameters such as geometry, material, and the thickness of the structure, the amount of pairing and therefore the sensitivity of the sensor were investigated and it was observed that Plasmonic nanobiosensors are sensitive to changes in the optical properties of the environment.
It is therefore concluded that, by selecting the appropriate structure of material and shell thickness, a high-sensitivity sensors in a wide range of optical wavelengths can be achieved