Dynamics, Efficiency, and Energy Distribution of Nonlinear Plasmon-Assisted Generation of Hot Carriers

Abstract

We employ nonlinear autocorrelation measurements to investigate plasmon-assisted hot carrier dynamics generated in optical gold antennas. We demonstrate that surface plasmons enable a nonlinear formation of hot carriers, providing thus a unique lever to optimize the energy distribution and generation efficiency of the photo-excited charges. The temporal response of the carriers' relaxation can be controlled within a range extending from 500 fs to 2.5 ps. By conducting a quantitative analysis of the dynamics, we determine the nonlinear absorption cross-section of individual optical antennas. As such, this work provides strong insights on the understanding of plasmon-induced hot carrier generation, especially in the view of applications where the time response plays a preponderant role.

“Hot” in Plasmonics: Temperature‐Related Concepts and Applications of Metal Nanostructures

“…In metal nanoparticles, the source term S 1 ( r , t ) depends on the photon flux and on the absorption cross section of the metal NPs . The latter depends directly on the surface plasmon resonances.…”

“…In metal nanoparticles, the source term S 1 (r,t) depends on the photon flux and on the absorption cross section of the metal NPs. [112] The latter depends directly on the surface plasmon resonances. In turn, the NP dielectric function changes value due to the ultrafast perturbation of the electron distribution.…”

Two-Photon Luminescence of Single Colloidal Gold Nanorods: Revealing the Origin of Plasmon Relaxation in Small Nanocrystals

“…The visible TPL emission band appears thus quite strongly connected to the GNR transverse plasmon resonance, thus leading to the mechanism illustrated in figure 7 where TPL is described by a 4-step mechanism 46 : (1) First two photons excite an electron from the d-band to the unoccupied states in the sp-band, this 1 st step benefiting from field enhancement at the GNR LSPR 31,47,48 .…”

Dispersion of the nonlinear susceptibility in gold nanoantennas

“…Secondly, the very same field enhancement that intensifies the nonlinear response at the nanoscale is heavily dependent on the geometrical properties of the plasmonic structures and it is extremely difficult to evaluate with precision, especially from the experimental point of view [6][7][8][9][10]20,28]. Definitely, the magnitude of the plasmonic enhancement must be known with high confidence for a precise analysis of the optical response since the efficiency of harmonics generation as well as of other multiphoton processes scales nonlinearly [6,29].…”