Deducing localized surface plasmon properties through analysis of the far-field optical spectra

This study establishes a method to determine the behaviors of localized surface plasmons (LSPs) vis-a-vis the absorption, scattering, and extinction cross-section spectra of metal nanoparticle arrays on dielectric interfaces, based on deductions from far-field reflectance and transmittance spectra by the modified Fresnel equations. Three types of Au nanoparticles, with varying densities, were constructed on quartz structures for the finite-difference time domain (FDTD) simulations, followed by calculations of the far-field optical spectra of the same. To confirm the validity of this method, the absorption, scattering, and extinction cross-section spectra of the nanoparticles were obtained directly from the FDTD simulation using the total-field/scattered-field method, comparing with the numerical conversions on the results of the simulated reflectance and transmittance spectra. Results show that this method can be valid when the local driving electric field of the LSP is located on the dielectric interface. However, the additional phase shift between the reflected waves by the LSPs and the dielectric interface will reduce the accuracy of this method for the scattering spectra.

Automated summary

This study establishes a method to determine the behaviors of localized surface plasmons (LSPs) on dielectric interfaces based on deductions from far-field reflectance and transmittance spectra. The method is validated through numerical calculations and compared with direct simulations. The results show that the method is effective for LSPs located on the dielectric interface.