scholarly journals Directional transport of fast electrons at the front target surface irradiated by intense femtosecond laser pulses with preformed plasma

2012 ◽  
Vol 30 (1) ◽  
pp. 39-43 ◽  
Author(s):  
X.X. Lin ◽  
Y.T. Li ◽  
B.C. Liu ◽  
F. Liu ◽  
F. Du ◽  
...  
Keyword(s):  
Electron Transport ◽  
Incidence Angle ◽  
Target Surface ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Fast Electrons ◽  
High Energy Electrons ◽  
Preformed Plasma ◽  
Directional Transport

AbstractThe effects of laser incidence angle on lateral fast electron transport at front target surface, when a plasma is preformed, irradiated by intense (>1018 W/cm2) laser pulses, are studied by Kα imaging technique and electron spectrometer. A horizontally asymmetric Kα halo, resulting from directional lateral electron transport and energy deposition, is observed for a large incidence angle (70°). Moreover, a group of MeV high energy electrons is emitted along target surface. It is believed that the deformed preplasma and the asymmetrical distribution of self-generated magnetic field, at large incidence angle, play an important role in the directional lateral electron transport.

scholarly journals Relativistic electron acceleration by surface plasma waves excited with high intensity laser pulses

2020 ◽  
Vol 8 ◽  
Author(s):  
X. M. Zhu ◽  
R. Prasad ◽  
M. Swantusch ◽  
B. Aurand ◽  
A. A. Andreev ◽  
...  
Keyword(s):  
Electron Flux ◽  
Incidence Angle ◽  
Laser Pulses ◽  
Electron Acceleration ◽  
High Energy ◽  
Laser Wavelength ◽  
Acceleration Process ◽  
Experimental Conditions ◽  
Preformed Plasma ◽  
Scale Length

The process of high energy electron acceleration along the surface of grating targets (GTs) that were irradiated by a relativistic, high-contrast laser pulse at an intensity $I=2.5\times 10^{20}~\text{W}/\text{cm}^{2}$ was studied. Our experimental results demonstrate that for a GT with a periodicity twice the laser wavelength, the surface electron flux is more intense for a laser incidence angle that is larger compared to the resonance angle predicted by the linear model. An electron beam with a peak charge of ${\sim}2.7~\text{nC}/\text{sr}$ , for electrons with energies ${>}1.5~\text{MeV}$ , was measured. Numerical simulations carried out with parameters similar to the experimental conditions also show an enhanced electron flux at higher incidence angles depending on the preplasma scale length. A theoretical model that includes ponderomotive effects with more realistic initial preplasma conditions suggests that the laser-driven intensity and preformed plasma scale length are important for the acceleration process. The predictions closely match the experimental and computational results.

Wavelength tunable, high energy femtosecond laser pulses directly generated from large-mode-area photonic crystal fiber

2012 ◽  
Vol 285 (10-11) ◽  
pp. 2715-2718 ◽  
Author(s):  
Chi Zhang ◽  
Yu-ying Zhang ◽  
Ming-lie Hu ◽  
Si-jia Wang ◽  
You-jian Song ◽  
...  
Keyword(s):  
Photonic Crystal ◽  
Femtosecond Laser ◽  
Photonic Crystal Fiber ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Large Mode Area ◽  
Crystal Fiber ◽  
Wavelength Tunable ◽  
Mode Area

scholarly journals Effects of oblique incidence and colliding pulses on laser-driven proton acceleration from relativistically transparent ultrathin targets

2020 ◽  
Vol 86 (5) ◽  
Author(s):  
J. Ferri ◽  
E. Siminos ◽  
L. Gremillet ◽  
T. Fülöp
Keyword(s):  
Oblique Incidence ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Reference Case ◽  
Proton Acceleration ◽  
Ion Energy ◽  
High Energies ◽  
Proton Charge ◽  
Induced Transparency

The use of ultrathin solid foils offers optimal conditions for accelerating protons to high energies from laser–matter interactions. When the target is thin enough that relativistic self-induced transparency sets in, all of the target electrons get heated to high energies by the laser, which maximizes the accelerating electric field and therefore the final ion energy. In this work, we first investigate how ion acceleration by ultraintense femtosecond laser pulses in transparent CH $_2$ solid foils is modified when turning from normal to oblique ( $45^\circ$ ) incidence. Due to stronger electron heating, we find that higher proton energies can be obtained at oblique incidence but in thinner optimum targets. We then show that proton acceleration can be further improved by splitting the laser pulse into two half-pulses focused at opposite incidence angles. An increase by ${\sim }30\,\%$ in the maximum proton energy and by a factor of ${\sim }4$ in the high-energy proton charge is reported compared to the reference case of a single normally incident pulse.

scholarly journals Femtosecond Laser Pulses Amplification in Crystals

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 347
Author(s):  
Dabu
Keyword(s):  
Femtosecond Laser ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Phase Matching ◽  
Chirped Pulse ◽  
Nonlinear Crystals ◽  
Pulse Amplification ◽  
Chirped Pulse Amplification ◽  
Laser Crystals

This paper describes techniques for high-energy laser pulse amplification in multi-PW femtosecond laser pulses. Femtosecond laser pulses can be generated and amplified in laser media with a broad emission spectral bandwidth, like Ti:sapphire crystals. By chirped pulse amplification (CPA) techniques, hundred-Joule amplified laser pulses can be obtained. Multi-PW peak-power femtosecond pulses are generated after recompression of amplified chirped laser pulses. The characteristics and problems of large bandwidth laser pulses amplification in Ti:sapphire crystals are discussed. An alternative technique, based on optical parametric chirped pulse amplification (OPCPA) in nonlinear crystals, is presented. Phase-matching conditions for broad bandwidth parametric amplification in nonlinear crystals are inferred. Ultra-broad phase matching bandwidth of more than 100 nm, able to support the amplification of sub-10 fs laser pulses, are demonstrated in nonlinear crystals, such as Beta Barium Borate (BBO), Potassium Dideuterium Phosphate (DKDP), and Lithium Triborate (LBO). The advantages and drawbacks of CPA amplification in laser crystals and OPCPA in nonlinear crystals are discussed. A hybrid amplification method, which combines low-medium energy OPCPA in nonlinear crystals with high energy CPA in large aperture laser crystals, is described. This technique is currently used for the development of 10-PW laser systems, with sub-20 fs pulse duration and more than 1012 intensity contrast of output femtosecond pulses.

scholarly journals Petawatt Femtosecond Laser Pulses from Titanium-Doped Sapphire Crystal

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 783
Author(s):  
Hiromitsu Kiriyama ◽  
Alexander S. Pirozhkov ◽  
Mamiko Nishiuchi ◽  
Yuji Fukuda ◽  
Akito Sagisaka ◽  
...  
Keyword(s):  
High Intensity ◽  
Short Pulse ◽  
Beam Quality ◽  
Laser Pulses ◽  
High Energy ◽  
Femtosecond Laser Pulses ◽  
Small Scale ◽  
Sapphire Crystal ◽  
Chirped Pulse Amplification ◽  
Ultra Short Pulse

Ultra-high intensity femtosecond lasers have now become excellent scientific tools for the study of extreme material states in small-scale laboratory settings. The invention of chirped-pulse amplification (CPA) combined with titanium-doped sapphire (Ti:sapphire) crystals have enabled realization of such lasers. The pursuit of ultra-high intensity science and applications is driving worldwide development of new capabilities. A petawatt (PW = 1015 W), femtosecond (fs = 10−15 s), repetitive (0.1 Hz), high beam quality J-KAREN-P (Japan Kansai Advanced Relativistic ENgineering Petawatt) Ti:sapphire CPA laser has been recently constructed and used for accelerating charged particles (ions and electrons) and generating coherent and incoherent ultra-short-pulse, high-energy photon (X-ray) radiation. Ultra-high intensities of 1022 W/cm2 with high temporal contrast of 10−12 and a minimal number of pre-pulses on target has been demonstrated with the J-KAREN-P laser. Here, worldwide ultra-high intensity laser development is summarized, the output performance and spatiotemporal quality improvement of the J-KAREN-P laser are described, and some experimental results are briefly introduced.

Terahertz radiation from a shallow incidence-angle InAs emitter in a magnetic field irradiated with femtosecond laser pulses

2001 ◽  
Vol 40 (9) ◽  
pp. 1369 ◽  
Author(s):  
Shingo Ono ◽  
Takeyo Tsukamoto ◽  
Eiji Kawahata ◽  
Takayuki Yano ◽  
Hideyuki Ohtake ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Femtosecond Laser ◽  
Terahertz Radiation ◽  
Incidence Angle ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses

scholarly journals 3-D aluminum nanostructure with microhole array synthesized by femtosecond laser radiation for enhanced light extinction

2021 ◽  
Author(s):  
Abdul Salam Mahmood ◽  
Krishnan Venkatakrishnan ◽  
Bo Tan
Keyword(s):  
Femtosecond Laser ◽  
Light Absorption ◽  
Target Surface ◽  
Laser Pulses ◽  
Pulse Frequency ◽  
Femtosecond Laser Pulses ◽  
Light Extinction ◽  
Ambient Conditions ◽  
Aluminum Target ◽  
Microhole Array

This article presents 3-D aluminum micro-nanostructures for enhanced light absorption. Periodic microhole arrays were created by firing a train of femtosecond laser pulses at megahertz pulse frequency onto the surface of an aluminum target at ambient conditions. The laser trains ablated the target surface and created microholes leading to the generation of deposited nanostructures inside and around the microholes. These micro-nanostructures showed enhanced light absorption, which is attributed to surface plasmonics induced by the generation of both nano- and microstructures. These micro-nanostructures may be promising for solar cell applications.

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