A surface plasmon biosensor based on sub-wavelength metal slit arrays

A novel surface plasmon sensor which is constructed with sub-wavelength metal slit arrays deposited on a buffer media layer is proposed. To obtain the maximum resonant transmission, the buffer layer is coated on a glass substrate and the refractive index of the buffer layer is selected close to that of the water environment. Based on rigorous coupled wave analysis, the numerical simulation shows that the resonant transmission is enhanced and the peak mediated by surface plasmon resonance is much sharper due to the buffer layer. Therefore, this surface plasmon sensor with a buffer layer provides an improved measurement precision in biosensing application.