Biosensor based on multiple metal layer-hole array

Abstract

Abstract We propose a biosensor which is sensitive to the refraction index (RI) of the tested liquid. The sensor is composed of a metal-insulator-metal structure based on periodic nanopore arrays, whose absorption spectrum exhibits a narrow peak at the resonant wavelength. The finite difference time domain method is used to simulate the proposed structure. The results show that there is a narrow resonant peak at the wavelength of 800 nm with RI of 1.33. By adding grooves on the lower metal layer, the maximum absorption rate increases to 99.7%. When RI varies in the range from 1.33 to 1.35, it can have a high sensitivity of 550 nm /RIU, a narrow half peak full width of 5.87 nm, and a figure of merit of 93.7. In addition, the absorption peak value also changes significantly with a sensitivity of 1845%/RIU, which can be used to measure the concentration of bovine serum albumin and other solutions to achieve biosensors.