Thermally-related nonlinear optical properties of gold nanospheres
Po-Ting Shen1*, Cheng-Wei Lin2, Hsiang-Lin Liu2, Shi-Wei Chu1
1Department of Physics, National Taiwan University, Taipei, Taiwan
2Department of Physics, National Taiwan Normal University, Taipei, Taiwan
* presenting author:Po-Ting Shen,
Recently, we have observed new nonlinearities, including saturation and reverse saturation, of single-nanoparticle scattering. There are four possible mechanisms: intraband transition, interband transition, hot electron, and hot lattice. By deriving the single-particle nonlinear index, we found that hot lattice is the most probable one. As a further evidence, temperature-dependent scattering of single particle is found, for the first time, and its amplitude correlates well to the nonlinear scattering theory based on hot lattice plus localized field enhancement. Our work features a new frontier of “hot lattice” plasmonics, and similar nonlinear behaviors are expected in other materials.

Keywords: thermal, nolinear optics, gold nanospheres, surface plasmon resonance, Mie scattering