Broadband Spectral Signature of the Ultrafast Transient Optical Response of Gold Nanorods

摘要: The ultrafast transient optical response of gold nanorods presents a complex spectral signature that is very sensitive to the nanoparticle aspect ratio. This stems from different electronic contributions photoinduced dynamics metal dielectric function, which modify transverse and longitudinal localized plasmon modes. Here, we analyze physical origins ensembles over whole visible range. Using broadband time-resolved spectroscopy, determine within first picoseconds after pump excitation colloidal solutions containing with mean ratios. Supported by model calculation, it shown contribution interband electron transitions dominates at ultrashort times, even for photon energies far below their threshold. At longer slower intraband transition component linked heating appears. We then describe how ensemble effect modifies th...