Polarization-resolved extinction and scattering cross-section of individual gold nanoparticles measured by wide-field microscopy on a large ensemble

Abstract

We report a simple, rapid, and quantitative wide-field technique to measure the optical extinction ${\sigma }_{\mathrm{ext}}$ and scattering ${\sigma }_{\mathrm{sca}}$ cross-section of single nanoparticles using wide-field microscopy enabling simultaneous acquisition of hundreds of nanoparticles for statistical analysis. As a proof of principle, we measured nominally spherical gold nanoparticles of 40\,nm and 100\,nm diameter and found mean values and standard deviations of ${\sigma }_{\mathrm{ext}}$ and ${\sigma }_{\mathrm{sca}}$ consistent with previous literature. Switching from unpolarized to linearly polarized excitation, we measured ${\sigma }_{\mathrm{ext}}$ as a function of the polarization direction, and used it to characterize the asphericity of the nanoparticles. The method can be implemented cost-effectively on any conventional wide-field microscope and is applicable to any nanoparticles.

References in corpus (1)

• Optical Properties of Isolated and Supported Metal Nanoparticles