scholarly journals Cylindrically and non-cylindrically symmetric expansion dynamics of tin microdroplets after ultrashort laser pulse impact

2021 ◽  
Vol 127 (2) ◽  
Author(s):  
Tiago de Faria Pinto ◽  
Jan Mathijssen ◽  
Randy Meijer ◽  
Hao Zhang ◽  
Alex Bayerle ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Droplet Deformation ◽  
Cylindrically Symmetric ◽  
Linearly Polarized ◽  
Particle Hydrodynamics ◽  
Deformation Dynamics ◽  
Smoothed Particle ◽  
Asymmetric Shock

AbstractIn this work, the expansion dynamics of liquid tin micro-droplets irradiated by femtosecond laser pulses were investigated. The effects of laser pulse duration, energy, and polarization on ablation, cavitation, and spallation dynamics were studied using laser pulse durations ranging from 220 fs to 10 ps, with energies ranging from 1 to 5 mJ, for micro-droplets with an initial radius of 15 and 23 $$\upmu$$ μ m. Using linearly polarized laser pulses, cylindrically asymmetric shock waves were produced, leading to novel non-symmetric target shapes, the asymmetry of which was studied as a function of laser pulse parameters and droplet size. A good qualitative agreement was obtained between smoothed-particle hydrodynamics simulations and high-resolution stroboscopic experimental data of the droplet deformation dynamics.

Ultrafast deformation dynamics of silver nanoparticles in glass induced by femtosecond laser pulses

2006 ◽  
Author(s):  
Gerhard Seifert ◽  
Alexander Podlipensky ◽  
Jens Lange ◽  
Herbert Hofmeister ◽  
Heinrich Graener
Keyword(s):  
Silver Nanoparticles ◽  
Femtosecond Laser ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Deformation Dynamics

scholarly journals Динамика спинорной экситон-поляритонной системы в латерально сжатых GaAs микрорезонаторах при резонансном фотовозбуждении

2018 ◽  
Vol 60 (8) ◽  
pp. 1567
Author(s):  
А.А. Деменев ◽  
Н.А. Гиппиус ◽  
В.Д. Кулаковский
Keyword(s):  
Laser Pulse ◽  
Spatial Coherence ◽  
Picosecond Laser ◽  
Threshold Value ◽  
Laser Pulses ◽  
Josephson Effects ◽  
High Q ◽  
Wide Range ◽  
Linearly Polarized ◽  
Polariton Branch

AbstractThe evolution of the spatial coherence and the polarization has been studied in a freely decaying polariton condensate that is resonantly excited by linearly polarized picosecond laser pulses at the lower and upper sublevels of the lower polariton branch in a high-Q GaAs-based microcavity with a reduced lateral symmetry without excitation of the exciton reservoir. It is found that the condensate inherits the coherence of the exciting laser pulse at both sublevels in a wide range of excitation densities and retains it for several dozen picoseconds. The linear polarization of the photoexcited condensate is retained only in the condensate at the lower sublevel. The linearly polarized condensate excited at the upper sublevel loses its stability at the excitation densities higher a threshold value: it enters a regime of internal Josephson oscillations with strongly oscillating circular and diagonal linear degrees of polarization. The polariton–polariton interaction leads to the nonlinear Josephson effects at high condensate densities. All the effects are well described in terms of the spinor Gross–Pitaevskii equations. The cause of the polarization instability of the condensate is shown to be the spin anisotropy of the polariton–polariton interaction.

scholarly journals A laser-plasma accelerator driven by two-color relativistic femtosecond laser pulses

2019 ◽  
Vol 5 (11) ◽  
pp. eaav7940 ◽  
Author(s):  
Song Li ◽  
Guangyu Li ◽  
Quratul Ain ◽  
Min Sup Hur ◽  
Antonio C. Ting ◽  
...  
Keyword(s):  
Laser Pulse ◽  
Laser Plasma ◽  
Second Harmonic ◽  
Laser Pulses ◽  
Theoretical Work ◽  
Femtosecond Laser Pulses ◽  
Plasma Accelerator ◽  
Positron Energy ◽  
Potential Applications ◽  
Laser Plasma Accelerator

A typical laser-plasma accelerator (LPA) is driven by a single, ultrarelativistic laser pulse from terawatt- or petawatt-class lasers. Recently, there has been some theoretical work on the use of copropagating two-color laser pulses (CTLP) for LPA research. Here, we demonstrate the first LPA driven by CTLP where we observed substantial electron energy enhancements. Those results have been further confirmed in a practical application, where the electrons are used in a bremsstrahlung-based positron generation configuration, which led to a considerable boost in the positron energy as well. Numerical simulations suggest that the trailing second harmonic relativistic laser pulse is capable of sustaining the acceleration structure for much longer distances after the preceding fundamental pulse is depleted in the plasma. Therefore, our work confirms the merits of driving LPAs by two-color pulses and paves the way toward a downsizing of LPAs, making their potential applications in science and technology extremely attractive and affordable.

scholarly journals Plasmonic layer-selective all-optical switching of magnetization with nanometer resolution

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
D. O. Ignatyeva ◽  
C. S. Davies ◽  
D. A. Sylgacheva ◽  
A. Tsukamoto ◽  
H. Yoshikawa ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Magnetic Recording ◽  
Optical Switching ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
All Optical ◽  
Polarization Axis ◽  
Linearly Polarized ◽  
All Optical Switching ◽  
Better Than

Abstract All-optical magnetization reversal with femtosecond laser pulses facilitates the fastest and least dissipative magnetic recording, but writing magnetic bits with spatial resolution better than the wavelength of light has so far been seen as a major challenge. Here, we demonstrate that a single femtosecond laser pulse of wavelength 800 nm can be used to toggle the magnetization exclusively within one of two 10-nm thick magnetic nanolayers, separated by just 80 nm, without affecting the other one. The choice of the addressed layer is enabled by the excitation of a plasmon-polariton at a targeted interface of the nanostructure, and realized merely by rotating the polarization-axis of the linearly-polarized ultrashort optical pulse by 90°. Our results unveil a robust tool that can be deployed to reliably switch magnetization in targeted nanolayers of heterostructures, and paves the way to increasing the storage density of opto-magnetic recording by a factor of at least 2.

scholarly journals Terahertz radiation driven by two-color laser pulses at near-relativistic intensities: Competition between photoionization and wakefield effects

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
P. González de Alaiza Martínez ◽  
X. Davoine ◽  
A. Debayle ◽  
L. Gremillet ◽  
L. Bergé
Keyword(s):  
Fluid Model ◽  
Maxwell Fluid ◽  
Electron Shell ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Pulse Generation ◽  
Fully Depleted ◽  
Particle In Cell ◽  
Linearly Polarized ◽  
Ponderomotive Forces

Abstract We numerically investigate terahertz (THz) pulse generation by linearly-polarized, two-color femtosecond laser pulses in highly-ionized argon. Major processes consist of tunneling photoionization and ponderomotive forces associated with transverse and longitudinal field excitations. By means of two-dimensional particle-in-cell (PIC) simulations, we reveal the importance of photocurrent mechanisms besides transverse and longitudinal plasma waves for laser intensities >1015 W/cm2. We demonstrate the following. (i) With two-color pulses, photoionization prevails in the generation of GV/m THz fields up to 1017 W/cm2 laser intensities and suddenly loses efficiency near the relativistic threshold, as the outermost electron shell of ionized Ar atoms has been fully depleted. (ii) PIC results can be explained by a one-dimensional Maxwell-fluid model and its semi-analytical solutions, offering the first unified description of the main THz sources created in plasmas. (iii) The THz power emitted outside the plasma channel mostly originates from the transverse currents.

scholarly journals Wakefield generation and electron acceleration by intense super-Gaussian laser pulses propagating in plasma

2013 ◽  
Vol 31 (4) ◽  
pp. 583-588 ◽  
Author(s):  
Pallavi Jha ◽  
Akanksha Saroch ◽  
Rohit Kumar Mishra
Keyword(s):  
Laser Pulse ◽  
Laser Pulses ◽  
Gaussian Pulse ◽  
Simulation Studies ◽  
One Dimensional ◽  
Particle In Cell ◽  
Peak Energy ◽  
Test Electron ◽  
Linearly Polarized ◽  
Relativistic Regime

AbstractEvolution of longitudinal electrostatic wakefields, due to the propagation of a linearly polarized super-Gaussian laser pulse through homogeneous plasma has been presented via two-dimensional particle-in-cell simulations. The wakes generated are compared with those generated by a Gaussian laser pulse in the relativistic regime. Further, one-dimensional numerical model has been used to validate the generated wakefields via simulation studies. Separatrix curves are plotted to study the trapping and energy gain of an externally injected test electron, due to the generated electrostatic wakefields. An enhancement in the peak energy of an externally injected electron accelerated by wakes generated by super-Gaussian pulse as compared to Gaussian pulse case has been observed.

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.

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