A self-referencing surface plasmon resonance sensor

A zero cross sensitivity (CS) deliverable self-referencing (S-R) surface plasmon resonance sensor (SPR) experimental scheme is presented based on the retroreflecting prism configuration with single spectroscopic read out. The relationship between external and internal incident angle in retroreflection configuration results in the excitation of two spectroscopically distinct surface plasmons (SPs) modes corresponding to each side of the prism. The characteristics of two SPs modes are independent and thus used in differential refractive index (RI) sensing via S-R modes technique. By applying SR sensing theory, it is shown that the CS can be minimized to zero through the demonstrated configuration. This configuration is flexible for using in wavelength interrogation measurement method as well. The excited SPs modes are also tunable to acquire either identical or non-identical sensitivity by selecting corresponding metal film thickness on the either sides of the prism. From the preliminary experimentation on SR configuration and theoretical investigation on deliverability of zero CS, it can be expected that the presented scheme is a better SR configuration for high accurate differential RI sensing applications.