Optimization of gold square-shaped nanopillars arrays for high-efficiency optronics

Parametric optimization of gold (Au) square-shaped nanopillars (AuNPLs) arrays deposited on glass substrate (AuNPLs/glass) was performed through optical characteristics for high-performance optical detection and biosensing purpose from visible to very near-infrared spectral (0.5 <= lambda <= 0.8 mu m). This is aimed at predicting optimum parameters which result in strong enhancement for next-generation optronic devices. The optimization parameters were limited to the AuNPLs height (H), the interslit distance (W-1), and the slit width (W-2) in investigating the optical characteristics of reflectance, transmittance, and absorption. In achieving this, the extraordinary surface plasmon resonance (SPR) mechanism was explored using 3D finite-differential time-domain (3D-FDTD) algorithm. Based on the periodical nature of the AuNPLs array, periodic boundary conditions (PBCs) and stretched coordinate perfectly matched layers (SCPML) boundaries were employed for the computation region with a plane wave source injection at normal incidence (theta = 0 degrees). The results revealed new insights on the AuNPLs/glass structure and might inspire potential applications such as photodetectors and biosensors with optimum device achieved by controlling H from 0.1 to 1.0 mu m while W-1 = 0.25 mu m and W-2 = 0.1 mu m are kept constants and spectroscopy with optimum device by controlling W-1 from 0.1 to 1.0 mu m while H = 0.4 mu m and W-2 = 0.1 mu m are maintained constants. Besides, application of biosensor performs sensitivity (S) of 380.14 nm/RIU (nanometer/refractive index unit) and 377.32 nm/RIU with corresponding highest figure of merit (FOM) of 8.02 RIU-1 and 11.11 RIU-1 for H = 400 nm and H = 600 nm, respectively.

Automated summary

Parametric optimization of gold square-shaped nanopillars arrays on glass substrate was performed to enhance optical detection and biosensing. The optical characteristics were investigated and insights on the structure were gained, suggesting potential applications.