RESUMO
In response to the incident light's electric field, the electron density oscillates in the plasmonic hotspots producing an electric current. Associated Ohmic losses raise the temperature of the material within the plasmonic hotspot above the melting point. A nanojet and nanosphere ejection can then be observed precisely from the plasmonic hotspots.
Assuntos
Lasers , Nanotecnologia/métodos , Nanopartículas Metálicas/química , Temperatura , Fatores de TempoRESUMO
Hot carrier-induced spin dynamics is analyzed in epitaxial Au/Fe/MgO(001) by a time domain approach. We excite a spin current pulse in Fe by 35 fs laser pulses. The transient spin polarization, which is probed at the Au surface by optical second harmonic generation, changes its sign after a few hundred femtoseconds. This is explained by a competition of ballistic and diffusive propagation considering energy-dependent hot carrier relaxation rates. In addition, we observe the decay of the spin polarization within 1 ps, which is associated with the hot carrier spin relaxation time in Au.
RESUMO
We have applied the surface-sensitive nonlinear optical technique of magnetization-induced second harmonic generation (MSHG) to plasmonic, magnetic nanostructures made of Ni. We show that surface plasmon contributions to the MSHG signal can reveal the direction of the magnetization. Both the plasmonic and the magnetic nonlinear optical responses can be tuned; our results indicate novel ways to combine nanophotonics, nanoelectronics, and nanomagnetics and suggest the possibility for large magneto-chiral effects in metamaterials.
Assuntos
Magnetismo , Nanopartículas Metálicas/química , Nanotecnologia/métodos , Níquel/química , Fenômenos Ópticos , RotaçãoRESUMO
Chiral spectroscopic study: The intensities of second harmonic generation chiral spectroscopy are obtained from the dispersion of the nonlinear optical susceptibility components, as a function of wavelength for helicenbisquinone thin films (see figure). A single formalism fits all the data simultaneously, and the findings constitute an important milestone towards the development of a new experimental technique.
