A biosensor based on periodic arrays of gold nanodisks under normal transmission

We present a biosensor based on periodic arrays of gold nanodisks patterned on top of a glass substrate. The sensor's resonance wavelength, peak linewidth and figure of merit were studied both in experiments and in simulations. We analyzed the dependence of the sensor's resolution on the inherent figure of merit of the sensor structure and the signal to noise ratio of the detection system. The best achieved refractive index resolution is 1.5 × 10−4 RIU and the detection limit on antigen–antibody binding is better than 1 ng/mL.

► We demonstrate the first biosensor based on periodic arrays of gold nanodisks.
► The figure of merit increases with increasing lattice constant for evanescent grating order range.
► We find that the sensor's resolution is determined by the figure of merit and signal to noise ratio both depending on the lattice constant of the array.
► We achieve a best figure of merit around 3.6, refractive index resolution 1.5 × 10−4 RIU, and detection limit for antigen–antibody binding is better than 1 ng/mL.