The cross-section shape-dependent responses of S and FOM of individual Au nanorod sensors

Abstract

Besides aspect ratio (AR) and localized surface plasmon resonance (LSPR) peak wavelength, the cross-section shape of individual Au nanorod sensors is also crucial factors controlling their plasmon sensitivities. These three effects have not been investigated simultaneously till now. In this paper, we numerically investigate nanorods’ cross-section-dependent responses both of refractive index sensitivity factor S and corresponding figure of merit FOM to their AR and LSPR peak wavelengths by discrete dipole approximation. The cross-section shapes are demonstrated to affect the values of S and FOM although it does not destroy the overall response tendency of S/FOM to LSPR peak wavelengths and AR. Their optimal LSPR spectral regions and AR are unveiled, which are revealed to be cross-section shape-dependent and independent, respectively. The triangular Au nanocolumn is revealed to provide good candidate for Au LSPR-based biological sensing and detection, whose optimal LSPR peak wavelength falls in the second near-infrared window.