[Phys-seminars] 2017-06-22 Lasers Seminar

barmash barmash at bgu.ac.il
Thu Jun 15 11:52:24 IDT 2017

Lasers Seminar

 DATE: 22-06-17

 TIME: 15:30

 PLACE: Physics building (#54) room 207

Nonlinear plasmonics at high temperatures

Yonatan Sivan, Unit of Electro-Optics engineering, Ben-Gurion University

Recently, intriguing experimental results of the scattering of intense visible CW light from single Au and Ag nanoparticles were reported in [1]. Specifically, it was shown that at moderately high incident intensities, the scattering was lower than the linear prediction, showing \"saturation-like\" behaviour, whereas for even higher incident intensities, the scattering grew rapidly, even exceeding the linear prediction. Notably, this is one of the highest nonlinear responses ever reported, as more than a 100% strong effect is obtained within a deep subwavelength volume, and probably the first quantitative experimental study of the slow nonlinearity of metals. Most remarkably, no convincing explanation to the physical origin of this effect was reported. We show that the initial decrease of the scattering can be explained by the thermal nonlinear optical response of the metal to CW light [2]. In contrast to the multitude of studies of the ultrafast regime and the electron tempe
 rature contribution, we provide an elaborate solid state model that explains for the first time, the dependence of the metal permittivity on the lattice temperature. Lastly, we discuss possible explanations of the consequent increase of scattering and discuss the applications of such slow nonlinearity, mostly in the domain of photo-chemistry and photo-catalysis, thermal emission engineering etc.. References 1 S.W.Chu et al., Saturation and reverse saturation of scattering in a single plasmonic nanoparticle. ACS Photon 2013;1:32–37. Y.-T. Chen et al., Study of Nonlinear Plasmonic Scattering in Metallic Nanoparticles. ACS Photonics 2016; 3:1432–1439. [2] Y. Sivan, S.W. Chu, Nonlinear plasmonics at high temperatures. Nanophotonics 2017; 6:317-328.

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