From Semiconductor to Metal in a Flash: Observing Ultrafast Laser-Induced Phase Transformations

ABSTRACTWe use a new broadband spectroscopic technique to measure ultrafast changes in the dielectric function of a material over the spectral range 1.5–3.5 eV following intense 70-fs laser excitation. The results reveal the nature of the phase transformations which occur in the material following excitation. We studied the response of GaAs and Si. For GaAs, there are three distinct regimes of behavior as the pump fluence is increased — lattice heating, lattice disordering, and a semiconductor-to-metal transition.

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Theoretical study of the ultrashort dynamics in graphene after fs-laser excitation

EPJ Web of Conferences ◽

10.1051/epjconf/201920505006 ◽

2019 ◽

Vol 205 ◽

pp. 05006 ◽

Cited By ~ 1

Author(s):

Krylow Sergej ◽

Garcia Martin E.

Keyword(s):

Decay Time ◽

Theoretical Study ◽

Laser Excitation ◽

Low Frequency ◽

Ultrafast Laser ◽

Ab Initio Molecular Dynamics ◽

Fast Decay ◽

Phonon Modes ◽

Fs Laser ◽

Dynamics Simulations

We report on the calculation of the full dynamics of graphene after ultrafast laser excitation using ab-initio molecular dynamics simulations. Our calculations show a biexponential decay of the (100) and (110) Bragg peaks in time, similar to experimental results. Furthermore, we calculate the time-evolution of the phonon energies averaged over sets of phonons, chosen by their phonon frequencies. Our results suggest that the fast decay time can be accounted by phonon-phonon interactions rather than the generation of SCOPs. The slower decay time is governed by the equilibration of the system with low frequency phonon modes.

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Ultrafast Laser Cleaning of Daguerreotypes

MRS Proceedings ◽

10.1557/opl.2011.734 ◽

2011 ◽

Vol 1319 ◽

Cited By ~ 1

Author(s):

Michael J. Abere ◽

Ryan D. Murphy ◽

Bianca Jackson ◽

Gerard Mourou ◽

Michel Menu ◽

...

Keyword(s):

Material Removal ◽

Silver Oxide ◽

Laser Pulses ◽

Silver Sulfide ◽

Ultrafast Laser ◽

Beam Diameter ◽

Chemical Cleaning ◽

Silver Substrate ◽

Fs Laser ◽

Lower Material

ABSTRACTAn ultrafast laser irradiation method for the removal of corrosion from Daguerreotypes without detrimentally affecting image quality has been developed. Corrosion products such as silver oxide and silver sulfide may be removed by chemical cleaning but these reactions are hard to control and are often damaging to the underlying silver, ruining the image. The Ti:Sapphire 150 fs laser pulses used in this study are focused to a beam diameter of 60 μm and are normally incident to the Daguerreotype. It was found that the corrosion layer has a lower material removal threshold than silver allowing for removal of corrosion with minimal removal of vital information contained in the silver substrate.

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Study of non-equilibrium thermal transport in Ge2Sb2Te5 thin films under ultrafast laser excitation using a photo-excited carrier integrated semiconductor model

Journal of Applied Physics ◽

10.1063/1.4993451 ◽

2017 ◽

Vol 122 (4) ◽

pp. 043104 ◽

Cited By ~ 3

Author(s):

Y. H. Wang ◽

F. R. Liu ◽

W. Q. Li ◽

T. Fan ◽

J. F. Yang ◽

...

Keyword(s):

Thin Films ◽

Thermal Transport ◽

Laser Excitation ◽

Ultrafast Laser ◽

Excited Carrier ◽

Non Equilibrium

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Ultrafast Laser Induced Phase Transformations in Amorphous GeSb Films

CLEO/Europe Conference on Lasers and Electro-Optics ◽

10.1109/cleoe.1998.719540 ◽

2005 ◽

Author(s):

K. Sokolowski-Tinten ◽

J. Solis ◽

J. Bialkowski ◽

J. Siegel ◽

C.N. Afonso ◽

...

Keyword(s):

Phase Transformations ◽

Ultrafast Laser

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Ultrafast Laser Processing for Lab-on-a-Chip Device Manufacture

MRS Proceedings ◽

10.1557/proc-850-mm1.3 ◽

2004 ◽

Vol 850 ◽

Author(s):

Koji Sugioka ◽

Ya Cheng ◽

Katsumi Midorikawa

Keyword(s):

Heat Treatment ◽

Laser Processing ◽

Lab On A Chip ◽

Ultrafast Laser ◽

Wet Etching ◽

Direct Write ◽

Electric Control ◽

Fs Laser ◽

Laser Direct Write ◽

Hollow Microstructures

ABSTRACT3D microstructuring of photosensitive glass is demonstrated by femtosecond (fs) laser for lab-on-a-chip manufacture. True 3D hollow microstructures embedded in the glass are fabricated by the fs laser direct write followed by heat treatment and successive wet etching. A variety of microcomponents for a lab-on-a-chip device like a microfluidics, a microvalve, a microoptics, a microlaser, etc. are fabricated by using this technique. The fs laser direct write process is also applied for selective metallization of internal walls of the hollow microstructures embedded in the glass for electric control of movement of the micromechanical components in the lab-on-a-chip device.

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