scholarly journals Enhancement of the laser-driven proton source at PHELIX

2020 ◽  
Vol 8 ◽  
Author(s):  
J. Hornung ◽  
Y. Zobus ◽  
P. Boller ◽  
C. Brabetz ◽  
U. Eisenbarth ◽  
...  
Keyword(s):  
Conversion Efficiency ◽  
Proton Energy ◽  
Incidence Angle ◽  
Normal Incidence ◽  
Laser Pulses ◽  
Ion Acceleration ◽  
Laser Polarization ◽  
Temporal Contrast ◽  
Proton Source ◽  
Accelerated Particles

We present a study of laser-driven ion acceleration with micrometre and sub-micrometre thick targets, which focuses on the enhancement of the maximum proton energy and the total number of accelerated particles at the PHELIX facility. Using laser pulses with a nanosecond temporal contrast of up to $10^{-12}$ and an intensity of the order of $10^{20}~\text{W}/\text{cm}^{2}$ , proton energies up to 93 MeV are achieved. Additionally, the conversion efficiency at $45^{\circ }$ incidence angle was increased when changing the laser polarization to p, enabling similar proton energies and particle numbers as in the case of normal incidence and s-polarization, but reducing the debris on the last focusing optic.

scholarly journals Accelerating ions with high-energy short laser pulses from submicrometer thick targets

2016 ◽  
Vol 4 ◽  
Author(s):  
F. Wagner ◽  
C. Brabetz ◽  
O. Deppert ◽  
M. Roth ◽  
T. Stöhlker ◽  
...  
Keyword(s):  
Focal Plane ◽  
Short Pulse ◽  
Laser Pulses ◽  
High Energy ◽  
Ion Acceleration ◽  
Temporal Contrast ◽  
Short Pulse Laser ◽  
Target Intensity ◽  
Short Laser Pulses ◽  
And Control

Using the example of the PHELIX high-energy short pulse laser we discuss the technical preconditions to investigate ion acceleration with submicrometer thick targets. We show how the temporal contrast of this system was improved to prevent pre-ionization of such targets on the nanosecond timescale. Furthermore the influence of typical fluctuations or uncertainties of the on-target intensity on ion acceleration experiments is discussed. We report how these uncertainties were reduced by improving the assessment and control of the on-shot intensity and by optimizing the positioning of the target into the focal plane. Finally we report on experimental results showing maximum proton energies in excess of 85 MeV for ion acceleration via the target normal sheath acceleration mechanism using target thicknesses on the order of one micrometer.

Structurally colored stainless steel processed by using femtosecond laser pulses

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040016
Author(s):  
Caizhen Yao ◽  
Yuan Li ◽  
Shizhen Xu ◽  
Xinxiang Miao ◽  
Yayun Ye ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Femtosecond Laser ◽  
Periodic Structures ◽  
Normal Incidence ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Control Surface ◽  
Laser Polarization ◽  
Ambient Conditions ◽  
In Situ Preparation

Structurally colored stainless steel (SS) surfaces were produced by using femtosecond laser at normal incidence at ambient conditions. The influence of laser polarization on the surface properties was investigated. The surface morphologies, roughness and color of the laser-treated surface were characterized by using environmental scanning electron microscope (ESEM), roughmeter and atomic force microscope (AFM). Results indicated that the circular polarization leads to more random structures than the horizontally linear polarization. Specimen with the highest surface roughness shows the brightest color. Different colors are cyclically exhibited by changing view angles due to different orders of diffraction. This investigation developed the technique of using femtosecond laser in situ preparation of periodic structures on 304 SS, and indicating that laser polarization is an important parameter to control surface structures to achieve different colors.

Efficiency enhancement of ion acceleration from thin target irradiated by multi-PW few-cycle laser pulses

2021 ◽  
Vol 28 (2) ◽  
pp. 023102
Author(s):  
X. Z. Wu ◽  
Z. Gong ◽  
Y. R. Shou ◽  
Y. H. Tang ◽  
J. Q. Yu ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Ion Acceleration ◽  
Efficiency Enhancement ◽  
Thin Target

Relativistic laser piston model: Ponderomotive ion acceleration in dense plasmas using ultraintense laser pulses

2009 ◽  
Vol 16 (8) ◽  
pp. 083103 ◽  
Author(s):  
T. Schlegel ◽  
N. Naumova ◽  
V. T. Tikhonchuk ◽  
C. Labaune ◽  
I. V. Sokolov ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Ion Acceleration ◽  
Dense Plasmas

Effect of temporally modified ultra-short laser pulses on ion acceleration from thin foil targets

2018 ◽  
Vol 25 (8) ◽  
pp. 083113 ◽  
Author(s):  
M. Tayyab ◽  
S. Bagchi ◽  
J. A. Chakera ◽  
R. A. Khan ◽  
P. A. Naik
Keyword(s):  
Thin Foil ◽  
Laser Pulses ◽  
Ion Acceleration ◽  
Short Laser Pulses

scholarly journals Laser contrast and other key parameters enhancing the laser conversion efficiency in ion acceleration regime

2018 ◽  
Vol 167 ◽  
pp. 02002 ◽  
Author(s):  
Lorenzo Torrisi
Keyword(s):  
Electric Field ◽  
Conversion Efficiency ◽  
Laser Light ◽  
Laser Intensity ◽  
Multilayered Structure ◽  
Maximum Energy ◽  
Ion Acceleration ◽  
Surface Geometry ◽  
Laser Parameters ◽  
Target Composition

Measurements of ion acceleration in plasma produced by fs lasers at intensity of the order of 1018 W/cm2 have been performed in different European laboratories. The forward emission in target-normal-sheath-acceleration (TNSA) regime indicated that the maximum energy is a function of the laser parameters, of the irradiation conditions and of the target properties.In particular the laser intensity and contrast play an important role to maximize the ion acceleration enhancing the conversion efficiency. Also the use of suitable prepulses, focal distances and polarized laser light has important roles. Finally the target composition, surface, geometry and multilayered structure, permit to enhance the electric field driving the forward ion acceleration.Experimental measurements will be reported and discussed.

All-optical cascaded ion acceleration in segmented tubes driven by multiple independent laser pulses

2019 ◽  
Vol 61 (11) ◽  
pp. 115005
Author(s):  
H He ◽  
B Qiao ◽  
X F Shen ◽  
W P Yao ◽  
Y L Yao ◽  
...  
Keyword(s):  
Laser Pulses ◽  
Ion Acceleration ◽  
All Optical

Stray light autocorrelation for the measurement of ultrashort laser pulses

2020 ◽  
Vol 87 (5) ◽  
pp. 312-322
Author(s):  
Anne-Sophie Rother ◽  
Peter Kohns ◽  
Georg Ankerhold
Keyword(s):  
Conversion Efficiency ◽  
Nonlinear Medium ◽  
Laser Pulses ◽  
High Energy ◽  
Ultrashort Laser Pulses ◽  
Stray Light ◽  
Dihydrogen Phosphate ◽  
Barium Borate ◽  
Promising Alternative ◽  
Ultrashort Laser

AbstractUltrashort laser pulses in the femtosecond range are of growing interest in medicine and micro material processing for industrial applications. The most interesting parameter is the pulse duration, which can only be measured by optical autocorrelation methods incorporating an optically nonlinear medium. Established methods mostly use monocrystalline beta barium borate (BBO) in transmission, exhibiting a high nonlinear conversion efficiency. However, this material is brittle, expensive and sophisticated in adjustment due to the necessary non-collinear phase matching. Since fiber-based high energy femtosecond laser systems become more and more achievable, the conversion efficiency of the nonlinear medium should no longer be seen as the restricting factor. Therefore, this research work discusses the suitability of several nonlinear media with differing translucency. Quartz, ammonium dihydrogen phosphate (ADP) and aluminum nitride (AlN) were compared in a standard autocorrelation setup and a novel versatile setup measuring frequency-doubled stray light. Best results were achieved with AlN, which appears to be a suitable and promising alternative material to BBO, reducing the expenses by two to three orders of magnitude.

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