Spectroscopic study of optically induced ultrafast electron dynamics in gold

Kruglyak, V. V.; Hicken, R. J.; Matousek, Pavel; Towrie, Michael

doi:10.1103/physrevb.75.035410

Cited by 19 publications

(10 citation statements)

References 24 publications

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“…Turning now to photoinduced TA, these have been reported for Au NPs in SiO 2 glasses, 24 sol–gel matrix, 23 embedded in mesoporous TiO 2 , 32 , 33 in 2D arrays, 21 and in water 35 , 39 , 49 , 64 , 65 and ethanol 49 or TR of bulk Au films. 66 All exhibit a profile with a decreased absorption of the LSPR and red and blue wings, often (but not always) with an isosbestic Δ A = 0 on the blue wing and on the red side and a shifting one as a function of time.…”

Section: Resultsmentioning

confidence: 99%

Disentangling Light- and Temperature-Induced Thermal Effects in Colloidal Au Nanoparticles

et al. 2022

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We present temperature-dependent (from room temperature to 80 °C) absorption spectra of Au/SiO 2 core–shell nanoparticles (NPs) (core diameter: ∼25 nm) in water in the range from 1.5 to 4.5 eV, which spans the localized surface plasmon resonance (LSPR) and the interband transitions. A decrease in absorption with temperature over the entire spectral range is observed, which is more prominent at the LSPR. These changes are well reproduced by theoretical calculations of the absorption spectra, based on the experimentally measured temperature-dependent real (ε 1 ) and imaginary (ε 2 ) parts of the dielectric constant of Au NPs and of the surrounding medium. In addition, we model the photoinduced response of the NPs over the entire spectral range. The experimental and theoretical results of the thermal heating and the simulations of the photoinduced heating are compared with the ultrafast photoinduced transient absorption (TA) spectra upon excitation of the LSPR. These show that while the latter is a reliable monitor of heating of the NP and its environment, the interband region mildly responds to heating but predominantly to the population evolution of charge carriers.

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Section: Resultsmentioning

confidence: 99%

Disentangling Light- and Temperature-Induced Thermal Effects in Colloidal Au Nanoparticles

et al. 2022

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“…(Photon energy 3 eV is larger than the highest value, 2.68 eV, reported for sub-picosecond-resolution experiments on gold 13 . Transient reflectivity signals at 2.84 eV and 3.06 eV have been reported with ~1.5 ps time resolution 20 .)…”

Section: Resultsmentioning

confidence: 99%

“…Here we propose a way to map the real contact area of nanoscale contacts: we investigate the mechanical contact between metal-coated materials in situ by the use of optically-excited electron transport probed on sub-picosecond time scales. Ultrafast non-equilibrium electron diffusion in metals has been extensively studied by ultrashort-time-scale transient optical reflectivity measurements 11 12 13 14 15 16 17 18 19 20 21 22 , and such techniques have been implemented to image buried metallic layers 23 . We harness such electrons here to map the mechanical contact between a gold-coated sphere and a gold-coated plane (a Hertzian-contact geometry), offering the crucial advantage of mapping of a nanoscale mechanical contact during loading: for separations greater than angstrom-order, the electrons cannot cross the gaps between the contacting solids, and so allow the selective sensing of the real contact area.…”

mentioning

confidence: 99%

Nanoscale mechanical contacts mapped by ultrashort time-scale electron transport

Tomoda

Dehoux

Iwasaki

et al. 2014

Sci Rep

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Mechanical contacts are crucial to systems in engineering, electronics and biology. The microscopic nature of the contacting surfaces determines how they mesh on the nanoscale. There is thus much interest in methods that can map the actual area of two surfaces in contact—the real contact area—during the loading or unloading phases. We address this problem using an ultrafast optical technique to generate non-equilibrium electrons that diffuse across a nanoscale mechanical contact between two thin gold films deposited on sapphire. We image this process in the contact and near-contact regions to micron resolution in situ using transient optical reflectivity changes on femtosecond time scales. By use of a model of the ultrashort-time electron dynamics, we account for an up to ~40% drop in the transient optical reflectivity change on contact. We thereby show how the real contact area of a nanoscale contact can be mapped. Applications include the probing of microelectronic mechanical devices.

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“…Energy transport after a very short laser pulse (in femtoseconds) absorption will be given. The equation for electron temperature can be written as [11][12][13][14][15][16] (1) and the equation for the lattice temperature is:…”

Section: Theorymentioning

confidence: 99%

Femtosecond Electronic Thermal Oscillation in Electron Temperature Dynamics in Thin Gold Film

Jasim¹,

Azawe²

2012

IOSRJAP

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High intense femtosecond laser pulse is irradiated on thin gold film. Electron temperature was evaluated using the two-temperature and the dual-phase lag models. Numerical results showed a thermal oscillation in electron temperature dynamics. To assess thermal oscillation, analytical solution of the characteristic equation for heat conduction was obtained by the Laplace transformation method and implied with the Van Neumann condition. More than one temperature locations in the surface of thin gold film were observed.Another feature was also observed from the numerical solutions was the shallow concentration of temperature distribution of the film. Instabilities and non-homogeneous temperature distribution on front surface of the gold target were also studied in terms of plume expansion. Plume expansion (in vacuum) in terms of Knudsen layer thickness will be presented for different laser fluence and pulse duration. These results suggest that the laser parameters can influence the plume characteristics. Plume expansion in two dimensions of the surface exposed to the laser will be presented in order to show that the plume expansion was abroad and can be interpreted in terms of laser fluence.

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Spectroscopic study of optically induced ultrafast electron dynamics in gold

Cited by 19 publications

References 24 publications

Disentangling Light- and Temperature-Induced Thermal Effects in Colloidal Au Nanoparticles

Disentangling Light- and Temperature-Induced Thermal Effects in Colloidal Au Nanoparticles

Nanoscale mechanical contacts mapped by ultrashort time-scale electron transport

Femtosecond Electronic Thermal Oscillation in Electron Temperature Dynamics in Thin Gold Film

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