Direct deconvolution of electric and magnetic responses of single nanoparticles by Fourier space surface plasmon resonance microscopy

We use polarization-resolved surface plasmon resonance microscopy to image single dielectric nanoparticles. In real space, the nanoparticles exhibit V-shape diffraction patterns due to the interference between the incident surface plasmon polariton wave and the evanescent scattered waves, which arise from the interplay between the electric and magnetic dipoles of the nanoparticle. By using cross-polarized Fourier space imaging to extract only the scattered waves, we find the angular far-field intensity corresponds very well to the near-field scattering distribution, as confirmed by both analytical and numerical calculations. As a result, we directly deconvolute the contributions of electric and magnetic dipoles to the scattered fields without involving near-field techniques.