Dual-spectral narrow bandwidth surface lattice resonance sensors

Abstract

Dual-spectral narrow bandwidth surface lattice resonance (SLR) sensors consisting of semiconductor/SiO2 nanoparticle dimer arrays are proposed to achieve two high figures of merit (FOM). We demonstrate that FOM can be optimized by the change of semiconductor nanoparticles’ shape. The best shape of Si nanoparticles with high FOM is pillar because of the narrowest FWHM of SLR. The FOM of Si/SiO2 nanopillar dimer array can reach a value of 180 due to the high sensitivity and narrow bandwidth. Besides, the influences of different structural parameters (such as the gap of the Si nanopillars in each dimer, Si nanopillars’ diameter and height) on FOM of Si/SiO2 nanopillar dimer arrays are investigated. In the trade-off between the strong SLR and the high FOM, the gap of 50[Formula: see text]nm, the Si nanopillars’ diameter of 80[Formula: see text]nm, and the Si nanopillars’ height of 100[Formula: see text]nm, are chosen as suitable values. Furthermore, a comparison of FOM between Si, Ge, GaAs nanopillars with fixed sizes is implemented to select the appropriate materials. The best semiconductor material to obtain a high FOM is Si because of a narrower FWHM and higher sensitivity. This work is of great significance for the design of multi-spectral SLR sensors.