Revealing the quadrupole radiation of liquid gallium nanospheres

Abstract

Gallium (Ga) nanospheres (NSs) with diameters ranging from 50 to 300 nm are fabricated by using femtosecond laser ablation. The forward scattering of large Ga nanospheres measured using dark-field microscopy is determined by the coherent interaction between dipole and quadrupole resonances while it becomes governed by the dipole resonance when evanescent wave excitation is employed. We demonstrate that the scattering spectrum and pattern of quadrupole of large Ga NS can be resolved by using a cross-polarized analyzer in the collection channel. The experimental observations agree well with the numerical simulation based on the complex refractive index of liquid Ga.

Substrate-Modulated Electric and Magnetic Resonances of Lithium Niobite Nanoparticles Illuminated by White Light

“…Metal nanoparticles, for example, can support surface plasmons, which can be used to concentrate light into subwavelength volumes and produce higher optical intensity [2][3][4][5][6], thus paving the way to break the diffraction limit down to the nanometer scale. These extraordinary properties can trigger numerous fascinating optical phenomena such as superlensing effects [7,8] and surface-enhanced Raman scattering [9,10]. However, the majority of these undergo Ohmic loss and lack of magnetic resonance, which inevitably limit their application.…”