Near field distributions of a dielectric nanoparticle at an interface. Electromagnetic field around a dielectric nanoparticle n = 2, k = 0, and r = 170 nm, embedded half in air, half in a substrate with refractive index (a) n = 1.5 and (b) n = 3. The dipole, the quadrupole, and the hexapole modes are shown for the wavelengths of 680/816 nm, 490/502 nm, and 396/346 nm, respectively, which correspond to the maxima in scattering, see Figure 8b (incident light from the top).
Schmid et al. Nanoscale Research Letters 2014 9:50 doi:10.1186/1556-276X-9-50