scholarly journals Non-Fourier Estimate of Electron Temperature in Case of Femtosecond Laser Pulses Interaction with Metals

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 606 ◽  
Author(s):  
Anca M. Bucă ◽  
Mihai Oane ◽  
Muhammad Arif Mahmood ◽  
Ion N. Mihăilescu ◽  
Andrei C. Popescu ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Electron Temperature ◽  
Relaxation Times ◽  
Gold Surface ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
New Approach ◽  
Thermal Fields ◽  
Coupling Factors

This work is devoted to the electron temperature variation in metals through interaction with femtosecond laser pulses. Our study was inspired by the last mathematical breakthroughs regarding the exact analytical solutions of the heat equation in the case of flash laser-matter interaction. To this purpose, the classical Anisimov’s two temperature model was extended via the 3D telegraph Zhukovsky equation. Based upon this new approach, the computational plots of electron thermal fields during the first laser pulse interaction with a gold surface were inferred. It is shown that relaxation times and coupling factors over electron thermal conductivities (g/K) govern the interaction between the laser pulse and metal sample during the first picoseconds. The lower the factor g/K, the higher the electron temperature becomes. In contrast, the lower the relaxation time, the lower the electron temperature.

scholarly journals Multiphotonk-resolved photoemission from gold surface states with 800-nm femtosecond laser pulses

2014 ◽  
Vol 90 (3) ◽  
Author(s):  
Fausto Sirotti ◽  
Nathan Beaulieu ◽  
Azzedine Bendounan ◽  
Mathieu G. Silly ◽  
Christian Chauvet ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Surface States ◽  
Gold Surface ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

Extraordinary enhanced absorptivity of gold surface ablated with femtosecond laser pulses

2008 ◽  
Author(s):  
A. Y. Vorobyev ◽  
Chunlei Guo ◽  
V. S. Makin ◽  
N. G. Kokody ◽  
V. M. Kuzmichev
Keyword(s):  
Femtosecond Laser ◽  
Gold Surface ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

scholarly journals Towards optimization of femtosecond laser pulse nanostructuring of targets for high-intensity laser experiments in vacuum

2021 ◽  
Vol 127 (7) ◽  
Author(s):  
A. Andreev ◽  
J. Imgrunt ◽  
V. Braun ◽  
I. Dittmar ◽  
U. Teubner
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
High Intensity ◽  
Extreme Ultraviolet ◽  
Theoretical Models ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Laser Development ◽  
Laser Experiments

AbstractThe interaction of intense femtosecond laser pulses with solid targets is a topic that has attracted a large amount of interest in science and applications. For many of the related experiments a large energy deposition or absorption as well as an efficient coupling to extreme ultraviolet (XUV), X-ray photon generation, and/or high energy particles is important. Here, much progress has been made in laser development and in experimental schemes, etc. However, regarding the improvement of the target itself, namely its geometry and surface, only limited improvements have been reported. The present paper investigates the formation of laser-induced periodic surface structures (LIPSS or ripples) on polished thick copper targets by femtosecond Ti:sapphire laser pulses. In particular, the dependence of the ripple period and ripple height has been investigated for different fluences and as a function of the number of laser shots on the same surface position. The experimental results and the formation of ripple mechanisms on metal surfaces in vacuum by femtosecond laser pulses have been analysed and the parameters of the experimentally observed “gratings” interpreted on base of theoretical models. The results have been specifically related to improve high-intensity femtosecond-laser matter interaction experiments with the goal of an enhanced particle emission (photons and high energy electrons and protons, respectively). In those experiments the presently investigated nanostructures could be generated easily in situ by multiple pre-pulses irradiated prior to a subsequent much more intense main laser pulse.

scholarly journals Clean source of soft X-ray radiation formed in supersonic Ar gas jets by high-contrast femtosecond laser pulses of relativistic intensity

2020 ◽  
Vol 8 ◽  
Author(s):  
Maria Alkhimova ◽  
Sergey Ryazantsev ◽  
Igor Skobelev ◽  
Alexey Boldarev ◽  
Jie Feng ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Argon Plasma ◽  
Plasma Source ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Average Charge ◽  
High Contrast ◽  
X Ray ◽  
Gas Jets

In this work, we optimized a clean, versatile, compact source of soft X-ray radiation $(E_{\text{x}\text{-}\text{ray}}\sim 3~\text{keV})$ with an yield per shot up to $7\times 10^{11}~\text{photons}/\text{shot}$ in a plasma generated by the interaction of high-contrast femtosecond laser pulses of relativistic intensity $(I_{\text{las}}\sim 10^{18}{-}10^{19}~\text{W}/\text{cm}^{2})$ with supersonic argon gas jets. Using high-resolution X-ray spectroscopy approaches, the dependence of main characteristics (temperature, density and ionization composition) and the emission efficiency of the X-ray source on laser pulse parameters and properties of the gas medium was studied. The optimal conditions, when the X-ray photon yield reached a maximum value, have been found when the argon plasma has an electron temperature of $T_{\text{e}}\sim 185~\text{eV}$ , an electron density of $N_{\text{e}}\sim 7\times 10^{20}~\text{cm}^{-3}$ and an average charge of $Z\sim 14$ . In such a plasma, a coefficient of conversion to soft X-ray radiation with energies $E_{\text{x}\text{-}\text{ray}}\sim 3.1\;(\pm 0.2)~\text{keV}$ reaches $8.57\times 10^{-5}$ , and no processes leading to the acceleration of electrons to MeV energies occur. It was found that the efficiency of the X-ray emission of this plasma source is mainly determined by the focusing geometry. We confirmed experimentally that the angular distribution of the X-ray radiation is isotropic, and its intensity linearly depends on the energy of the laser pulse, which was varied in the range of 50–280 mJ. We also found that the yield of X-ray photons can be notably increased by, for example, choosing the optimal laser pulse duration and the inlet pressure of the gas jet.

Modeling of Surface Manipulation by Femtosecond Laser Pulses

1999 ◽  
Vol 573 ◽  
Author(s):  
A. S. Gruzdeva ◽  
V. E. Gruzdev
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Electromagnetic Waves ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Formation Processes ◽  
Linear And Nonlinear ◽  
Nonlinear Light Scattering ◽  
Fundamental Physical ◽  
Laser Pulse Interaction

ABSTRACTThere are discussed some fundamental physical aspects of surface manipulation by femtosecond laser pulses. Among touched on problems are formation processes of shock electromagnetic waves and surface ripple structures. Proposed theoretical model of femtosecond laser-pulse interaction with matter is illustrated by results of FDTD modeling of linear and nonlinear light scattering by rough surface. Possibility of surface roughness modification and required for that optimal laser-pulse parameters are discussed on the bases of obtained results.

Investigation of characteristic x-rays and hot-electron temperature in the interaction of normally incident femtosecond laser pulses with nanostructured foils

2014 ◽  
Vol 89 (7) ◽  
pp. 075605 ◽  
Author(s):  
O F Kostenko ◽  
A V Ovchinnokov ◽  
O V Chefonov ◽  
S A Romashevskiy ◽  
V P Petrovskiy ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Electron Temperature ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
X Rays ◽  
Hot Electron

SECONDARY CONVERGENCE IN FEMTOSECOND LASER TRAPPING

2010 ◽  
Vol 24 (16) ◽  
pp. 1739-1746 ◽  
Author(s):  
YUQIANG JIANG ◽  
CUNGEN MA ◽  
ISAMU OH ◽  
YOICHIROH HOSOKAWA ◽  
HIROSHI MASUHARA
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Threshold Value ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Polystyrene Bead ◽  
Laser Trapping ◽  
Pass Through

When femtosecond laser pulses pass through a trapped polystyrene bead, water breakdown is induced even though the energy of laser pulse is much lower compared to the threshold value of breakdown when the femtosecond laser directly irradiates in water. This mechanism is assigned to the secondary convergence of the laser by the trapped bead.

Nanostructuring Borosilicate Glass With Near-Field Enhanced Energy Using a Femtosecond Laser Pulse

2006 ◽  
Vol 129 (1) ◽  
pp. 53-59 ◽  
Author(s):  
Alex Heltzel ◽  
Arvind Battula ◽  
J. R. Howell ◽  
Shaochen Chen
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Borosilicate Glass ◽  
Substrate Surface ◽  
Near Field ◽  
Planck Equation ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Avalanche Ionization ◽  
Avalanche Process

A model based on the evolution of electron density derived from the Fokker-Planck equation has been built to describe ablation of dielectrics during femtosecond laser pulses. The model is verified against an experimental investigation of borosilicate glass with a 200fs laser pulse centered at 780nm wavelength in a range of laser energies. The ablation mechanisms in dielectrics include multi-photon ionization (MPI) and avalanche ionization. MPI dominates the ionization process during the first stages of the laser pulse, contributing seed electrons which supply avalanche ionization. The avalanche process initiates and becomes responsible for the majority of free-electron generation. The overall material removal is shown to be highly dependent upon the optical response of the dielectric as plasma is formed. The ablation model is employed to predict the response of borosilicate glass to an enhanced electromagnetic field due to the presence of microspheres on the substrate surface. It is shown that the diffraction limit can be broken, creating nanoscale surface modification. An experimental study accompanies the model, with AFM and SEM characterizations that are consistent with the predicted surface modifications.

scholarly journals Femtosecond Laser Pulses: Generation, Measurement and Propagation

2021 ◽  
Author(s):  
Mounir Khelladi
Keyword(s):  
Laser Pulse ◽  
Femtosecond Laser ◽  
Ultrashort Laser Pulse ◽  
Short Pulse ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Light Pulses ◽  
Large Bandwidth ◽  
Temporal Shape ◽  
Ultrashort Laser

In this contribution some basic properties of femtosecond laser pulse are summarized. In sections 2.1–2.5 the generation of femtosecond laser pulses via mode locking is described in simple physical terms. In section 2.6 we deal with measurement of ultrashort laser pulses. The characterization of ultrashort pulses with respect to amplitude and phase is therefore based on optical correlation techniques that make of the short pulse itself. In section 3 we start with the linear properties of ultrashort light pulses. However, due to the large bandwidth, the linear dispersion is responsible for dramatic effects. To describe and manage such dispersion effects a mathematical description of an ultrashort laser pulse is given first before we continue with methods how to change the temporal shape via the frequency domain. The chapter ends with a paragraph of the wavelet representation of an ultrashort laser pulse.

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