Figure 1

Darkfield hyperspectral (HS) data of AuNPs in various refractive index media to confirm spectral sensitivity. (A) HS images (taken at 40x magnification) of 100-nm AuNPs immobilized on a glass slide and imaged in air (n = 1.00), water (n = 1.33), or glycerol (n = 1.47), respectively. Inset shows a selected NP (or NP cluster) at higher magnification. (B) Scattering spectra extracted from HS image for a specific NP or NP cluster indicated by a dotted rectangle in part A. (C) Theoretical scattering spectra calculated based on Mie scattering theory code for 100-nm AuNPs in a homogeneous dielectric environment.