Optimization of plasmonic nanohole array sensor-design for biosensing application

Abstract

We employed the finite-difference time-domain (FDTD) simulation method for a wide range of device parameters. The optimization process was carried out for the period range of 100 &#8211 500 nm and hole diameter of 50 &#8211 300 nm. All these structures show a shift in the resonance wavelength for the change in the refractive index of the surrounding medium. We evaluated the performance of the device by simulating the structures for refractive index (RI) range of 1 to 2 with a resolution of 0.1 and recorded the transmitted intensity at wavelength of 626 nm and 501nm. According to the simulation data, the device with period 150 nm and hole size of 100nm on a 150nm thick gold film shows a linear response to the change in the refractive index of the surrounding medium. The result shows a shift >1.0 unit in the ratio of transmittance at wavelength 626 to 501 nm for each 0.1unit change in RI. This shift is more significant, i.e., of 1.6 unit for the change in the RI from 1.4 to 1.5. Since the device shows a linear response even for the change in RI from 1.4 to 1.5, which is the RI range of cells and biomolecules, therefore the design is suitable for bio sensing application.ese structures show a shift in the resonance wavelength for the change in the refractive index of the surrounding medium. We evaluated the performance of the device by simulating the structures for refractive index (RI) range of 1 to 2 with a resolution of 0.1 and recorded the transmitted intensity at wavelength of 626 nm and 501nm. According to the simulation data, the device with period 150 nm and hole size of 100nm on a 150nm thick gold film shows a linear response to the change in the refractive index of the surrounding medium. The result shows a shift >1.0 unit in the ratio of transmittance at wavelength 626 to 501 nm for each 0.1unit change in RI. This shift is more significant, i.e., of 1.6 unit for the change in the RI from 1.4 to 1.5. Since the device shows a linear response even for the change in RI from 1.4 to 1.5, which is the RI range of cells and biomolecules, therefore the design is suitable for bio sensing application.