Heat Transfer Across Metal-Dielectric Interfaces During Ultrafast-Laser Heating

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Liang Guo ◽  
Stephen L. Hodson ◽  
Timothy S. Fisher ◽  
Xianfan Xu
Keyword(s):  
Heat Transfer ◽  
Contact Resistance ◽  
Laser Heating ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrafast Laser ◽  
Dielectric Substrates ◽  
Electron Phonon Coupling ◽  
Dielectric Interfaces ◽  
Investigate Heat Transfer

Heat transfer across metal-dielectric interfaces involves transport of electrons and phonons accomplished either by coupling between phonons in metal and dielectric or by coupling between electrons in metal and phonons in dielectric. In this work, we investigate heat transfer across metal-dielectric interfaces during ultrafast-laser heating of thin metal films coated on dielectric substrates. By employing ultrafast-laser heating that creates strong thermal nonequilibrium between electrons and phonons in metal, it is possible to isolate the effect of the direct electron–phonon coupling across the interface and thus facilitate its study. Transient thermo-reflectance measurements using femtosecond laser pulses are performed on Au–Si samples while the simulation results based on a two-temperature model are compared with the measured data. A contact resistance between electrons in Au and phonons in Si represents the coupling strength of the direct electron–phonon interactions at the interface. Our results reveal that this contact resistance can be sufficiently small to indicate strong direct coupling between electrons in metal and phonons in dielectric.

Heat Transfer Across Metal-Dielectric Interfaces During Ultrafast-Laser Heating

2011 ◽  
Author(s):  
Liang Guo ◽  
Stephen L. Hodson ◽  
Timothy S. Fisher ◽  
Xianfan Xu
Keyword(s):  
Heat Transfer ◽  
Laser Heating ◽  
Ultrafast Laser ◽  
Direct Coupling ◽  
Phonon Coupling ◽  
Coupled Transport ◽  
Dielectric Interface ◽  
Electron Phonon Coupling ◽  
Measurement Results ◽  
Dielectric Interfaces

Heat transfer across a metal-dielectric interface involves coupled transport of electrons and phonons in metal and phonons in dielectric, which can be accomplished by coupling between phonons in metal and dielectric or direct coupling between electrons in metal and phonons in dielectric. Direct electron-phonon coupling across the metal-dielectric interface is neglected in some studies [1, 2] but considered in some others [3–5]. We investigate heat transfer across metal-dielectric interfaces during ultrafast-laser heating by employing transient thermo-reflectance (TTR) measurements on Au-Si samples. With ultrafast-laser heating that creates strong thermal non-equilibrium between electrons and phonons in metal, it is possible to isolate the effect of direct electron-phonon coupling across the interface. Simulation results based on the two-temperature model (TTM) are compared with the measurement results. The comparison shows a strong direct coupling between electrons in metal and phonons in dielectric.

The role of electron–phonon coupling in ultrafast laser heating

2005 ◽  
Vol 17 (1) ◽  
pp. 63-68 ◽  
Author(s):  
J. K. Chen ◽  
W. P. Latham ◽  
J. E. Beraun
Keyword(s):  
Laser Heating ◽  
Ultrafast Laser ◽  
Phonon Coupling ◽  
Electron Phonon Coupling

scholarly journals Ultrafast-laser-inscribed 3D integrated photonics: challenges and emerging applications

Nanophotonics ◽  
2015 ◽  
Vol 4 (3) ◽  
pp. 332-352 ◽  
Author(s):  
S. Gross ◽  
M. J. Withford
Keyword(s):  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrafast Laser ◽  
Integrated Photonics ◽  
Transparent Dielectrics ◽  
Wide Range ◽  
The Many ◽  
Quantum Photonics

AbstractSince the discovery that tightly focused femtosecond laser pulses can induce a highly localised and permanent refractive index modification in a large number of transparent dielectrics, the technique of ultrafast laser inscription has received great attention from a wide range of applications. In particular, the capability to create three-dimensional optical waveguide circuits has opened up new opportunities for integrated photonics that would not have been possible with traditional planar fabrication techniques because it enables full access to the many degrees of freedom in a photon. This paper reviews the basic techniques and technological challenges of 3D integrated photonics fabricated using ultrafast laser inscription as well as reviews the most recent progress in the fields of astrophotonics, optical communication, quantum photonics, emulation of quantum systems, optofluidics and sensing.

scholarly journals Генерация суперконтинуума в режиме филаментации в водяной капле с наночастицами серебра при низкой температуре

2020 ◽  
Vol 128 (12) ◽  
pp. 1821
Author(s):  
Н.А. Мыслицкая ◽  
А.В. Цибульникова ◽  
В.А. Слежкин ◽  
И.Г. Самусев ◽  
Ю.Н. Антипов ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Femtosecond Laser ◽  
Emission Spectrum ◽  
Heat Wave ◽  
Water Droplet ◽  
Droplet Diameter ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Transfer Processes ◽  
Localized Plasmons

The supercontinuum generation in water droplets with nanoparticles of citrate silver in the temperature range of 2–22 °C, as well as in the ice droplets frozen to −15.0 °C, has been studied. It was found that the intensity of the supercontinuum emission under the excitation by a train of femtosecond laser pulses exponentially decays along the droplet diameter and it increases linearly with increasing NP concentration. The emission spectrum of supercontinuum in water droplet with NPs and the generation of localized plasmons with fluorescence at the 430 nm wavelength was studied. The movement of a heat wave along the diameter of a small frozen drop with a speed of 190 mm / s accompanying exponentially decaying supercontinuum radiation was recorded. The modeling of heat transfer processes in the frozen droplet during the formation of a heat wave has been carried out.

scholarly journals Deposition of fibrous nanostructure by ultrafast laser ablation

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan
Keyword(s):  
Laser Ablation ◽  
Research Work ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Vapor Condensation ◽  
Single Step ◽  
Ultrafast Laser ◽  
Ambient Atmosphere ◽  
Pass Through ◽  
Ultrafast Laser Ablation

This research work demonstrated that laser-induced reverse transfer (LIRT) can be used for controllable site-specific deposition of fibrous nanostructure. The LIRT method makes it achievable to generate and deposit fibrous nanostructure of a wide variety of materials on a transparent acceptor in a single-step process at an ambient condition. The deposition of fibrous nanostructure was conducted using ultrafast laser ablation of silicon and aluminum targets placed behind a glass acceptor. Femtosecond laser pulses pass through the transparent acceptor and hit the bulk donor. Consequently a mass quantity of nanoparticles ablates from the donor and then aggregates and forms a porous fibrous nanostructure on the transparent acceptor. Our experiments demonstrated that the gap between the target and the glass acceptor was critical in the formation and accumulation of nanofibers and it determines the density of the formed nanostructure. The formation mechanism of the nanostructures can be explained by the well-established theory of vapor condensation within the plume induced by ultrafast laser ablation. Experimental results also show that the length of the nanostructure can be controlled by the gap between the target and glass acceptor. Lastly, energy-dispersive x-ray spectroscopy (EDS) analysis shows the oxygen concentration in the nanofibrous structure which is associated with oxidation of ablated material at ambient atmosphere.

Numerical Analysis on the Feasibility of Laser Microwelding of Metals by Femtosecond Laser Pulses Using ABAQUS

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
Dongkyun Lee ◽  
Elijah Kannatey-Asibu
Keyword(s):  
Pulse Duration ◽  
Ultrafast Lasers ◽  
Short Pulse ◽  
Material Model ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrafast Laser ◽  
Temperature Model ◽  
Laser Microwelding ◽  
Two Temperature

Ultrafast lasers of subpicosecond pulse duration have the potential for laser microwelding of micronscale fusion zone. Due to the extremely short pulse duration, laser-metal interaction involving ultrafast laser pulses should be analyzed using the two-temperature model. In this study, the two-temperature model is analyzed using ABAQUS to study the feasibility of laser microwelding with ultrafast laser. A material model is constructed using material properties and the subsurface boiling model. The model is validated using experimental results from the literature. Laser processing parameters of repetition rate, pulse duration, and focal radius are then investigated, in terms of molten pool generated in the material and requirements on those parameters for laser microwelding using ultrafast lasers are discussed.

Influence of heat transfer on nodule height of microstructured silicon fabricated by femtosecond laser pulses

2014 ◽  
Vol 118 (2) ◽  
pp. 327-331
Author(s):  
Yan Peng ◽  
XiangQian Chen ◽  
YunYan Zhou ◽  
Kun Luo ◽  
YiMing Zhu
Keyword(s):  
Heat Transfer ◽  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

scholarly journals Laser-assisted formation of luminescent domains in metal- or semiconductor-doped silicate and phosphate glasses

2021 ◽  
Vol 2015 (1) ◽  
pp. 012163
Author(s):  
A.S. Lipatiev ◽  
G.Yu. Shakhgildyan ◽  
M.P. Vetchinnikov ◽  
S.V. Lotarev ◽  
V.N. Sigaev
Keyword(s):  
Femtosecond Laser ◽  
Silicate Glass ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Ultrafast Laser ◽  
Phosphate Glasses ◽  
Photoluminescence Intensity ◽  
Photoluminescence Properties ◽  
Ultrafast Laser Pulses ◽  
Cds Nanocrystals

Abstract In this study, silicate and phosphate glasses doped with Ag or CdS were exposed to femtosecond laser pulses and photoluminescence properties of the laser-written domains were investigated. Laser writing in phosphate glass doped with CdS was found to induce very weak photoluminescence, while laser-written domains in silicate glass had a comparatively high photoluminescence intensity, that was assigned to the formation of the sulphur vacancies in the CdS nanocrystals precipitated under the ultrafast laser pulses. Observed photoluminescence bands in Ag-containing glasses we assigned to the formation of different silver nanospecies which provide photoluminescence bands with the maxima at 685 and 600 nm in Ag-doped silicate and phosphate glasses, respectively.

scholarly journals Fabricating waveguide Bragg gratings (WBGs) in bulk materials using ultrashort laser pulses

Nanophotonics ◽  
2017 ◽  
Vol 6 (5) ◽  
pp. 743-763 ◽  
Author(s):  
Martin Ams ◽  
Peter Dekker ◽  
Simon Gross ◽  
Michael J. Withford
Keyword(s):  
Femtosecond Laser ◽  
Ion Beam ◽  
Laser Pulses ◽  
Bragg Gratings ◽  
Femtosecond Laser Pulses ◽  
Ultrafast Laser ◽  
Ultrashort Laser Pulses ◽  
Clean Room ◽  
Bulk Materials ◽  
Ultrashort Laser

AbstractOptical waveguide Bragg gratings (WBGs) can be created in transparent materials using femtosecond laser pulses. The technique is conducted without the need for lithography, ion-beam fabrication methods, or clean room facilities. This paper reviews the field of ultrafast laser-inscribed WBGs since its inception, with a particular focus on fabrication techniques, WBG characteristics, WBG types, and WBG applications.

scholarly journals Deposition of fibrous nanostructure by ultrafast laser ablation

2021 ◽  
Author(s):  
Amirhossein Tavangar ◽  
Bo Tan ◽  
Krishnan Venkatakrishnan
Keyword(s):  
Laser Ablation ◽  
Research Work ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Vapor Condensation ◽  
Single Step ◽  
Ultrafast Laser ◽  
Ambient Atmosphere ◽  
Pass Through ◽  
Ultrafast Laser Ablation

This research work demonstrated that laser-induced reverse transfer (LIRT) can be used for controllable site-specific deposition of fibrous nanostructure. The LIRT method makes it achievable to generate and deposit fibrous nanostructure of a wide variety of materials on a transparent acceptor in a single-step process at an ambient condition. The deposition of fibrous nanostructure was conducted using ultrafast laser ablation of silicon and aluminum targets placed behind a glass acceptor. Femtosecond laser pulses pass through the transparent acceptor and hit the bulk donor. Consequently a mass quantity of nanoparticles ablates from the donor and then aggregates and forms a porous fibrous nanostructure on the transparent acceptor. Our experiments demonstrated that the gap between the target and the glass acceptor was critical in the formation and accumulation of nanofibers and it determines the density of the formed nanostructure. The formation mechanism of the nanostructures can be explained by the well-established theory of vapor condensation within the plume induced by ultrafast laser ablation. Experimental results also show that the length of the nanostructure can be controlled by the gap between the target and glass acceptor. Lastly, energy-dispersive x-ray spectroscopy (EDS) analysis shows the oxygen concentration in the nanofibrous structure which is associated with oxidation of ablated material at ambient atmosphere.

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