Phonon dynamics of single nanoparticles studied using confocal pump-probe backscattering

摘要

Confocal pump-probe backscattering was used to study phonon dynamics of single nanoparticles, which can extend to confocal pump-probe microscopy for investigating carrier dynamics of single nanomaterials. Compared to previous pump-probe microscopy studies, in which nonlinear optical generation was widely utilized, spectral filters were employed in this work to separate the spectra from the optical pulses for pump/probe beams. This not only reduces the complexity of the experimental setup but can also circumvent the aberration issue. Phonon dynamics, including acoustic vibrations and heat diffusion, of a single gold nanoparticle were measured with a temporal delay of 8 ns, and a 0.5K rise in the temperature of the surrounding media was resolved. The relative optical changes induced by the photoexcitation of the pump pulses in confocal reflection pump-probe traces were orders of magnitude larger than those in typical transmission-type pump probe traces. Published by AIP Publishing.