scholarly journals Interaction of high intensity picosecond laser pulses with large preformed plasmas

1998 ◽  
Vol 16 (1) ◽  
pp. 101-113 ◽  
Author(s):  
D. Riley ◽  
R.A. Smith ◽  
A. J. MacKinnon ◽  
O. Willi ◽  
M.H.R. Hutchinson
Keyword(s):  
High Intensity ◽  
Laser Energy ◽  
Incident Light ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Resonance Absorption ◽  
Emission Data ◽  
X Ray ◽  
Spatially Resolved ◽  
Stimulated Brillouin

The interaction of short (1−2 ps) laser pulses with solid targets at irradiances of over 1016 Wcm−2, in the presence of a substantial prepulse has been investigated. High absorption of laser energy is found even at high angles of incidence, with evidence for a resonance absorption peak being found for S, P, and circular polarizations. It is considered that this may be a result of refraction and beam filamentation, which causes loss of distinct polarization. Measurements of hard X-ray emission (∼ 100 keV) confirm a resonance absorption type peak at 45−50°, again for all three cases. Typically, 5−15% of the incident light is back-reflected by stimulated Brillouin scatter, with spatially resolved spectra showing evidence of beam hot-spots at high intensity. The possibility that filamentation and refraction of the beam can explain the lack of polarization dependence in the absorption and hard X-ray emission data is discussed.

scholarly journals Generation of High-Power High-Intensity Short X-Ray Free-Electron-Laser Pulses

2018 ◽  
Vol 120 (1) ◽  
Author(s):  
Marc W. Guetg ◽  
Alberto A. Lutman ◽  
Yuantao Ding ◽  
Timothy J. Maxwell ◽  
Franz-Josef Decker ◽  
...  
Keyword(s):  
High Power ◽  
Free Electron ◽  
High Intensity ◽  
Free Electron Laser ◽  
Laser Pulses ◽  
X Ray

scholarly journals Scanning electron microscope studies on laser ablation of solids

2019 ◽  
Vol 37 (01) ◽  
pp. 101-109 ◽  
Author(s):  
Mohamed E. Shaheen ◽  
Joel E. Gagnon ◽  
Brian J. Fryer
Keyword(s):  
Pulse Width ◽  
Laser Energy ◽  
Laser System ◽  
Picosecond Laser ◽  
Laser Pulses ◽  
Ablation Rate ◽  
Laser Wavelength ◽  
High Laser Fluence ◽  
Electron Imaging ◽  
Scanning Electron

AbstractThis study investigates the interaction of picosecond laser pulses with sapphire and brass in air using scanning electron microscopy. A picosecond laser system operating at a wavelength of 785 nm, pulse width of 110 ps, and variable repetition rate (1–1000 Hz) was used in this study. The pulse width applied in this work was not widely investigated as it lies in the gap between ultrashort (femtosecond) and long (nanosecond) pulse width lasers. Different surface morphologies were identified using secondary electron and backscattered electron imaging of the ablated material. Thermal ablation effects were more dominant in brass than in sapphire. Exfoliation and fractures of sapphire were observed at high laser fluence. Compared with brass, multiple laser pulses were necessary to initiate ablation in sapphire due to its poor absorption to the incident laser wavelength. Ablation rate of sapphire was lower than that of brass due to the dissipation of a portion of the laser energy due to heating and fracturing of the surface.

Transient Ne-like Cr x-ray lasers driven by picosecond laser pulses

1998 ◽  
Vol 5 (1) ◽  
pp. 266-272 ◽  
Author(s):  
Ying Zhang ◽  
Jie Zhang ◽  
Shi-bing Liu ◽  
Dao-zhong Zhang ◽  
Yu-xin Nie
Keyword(s):  
Picosecond Laser ◽  
Laser Pulses ◽  
X Ray ◽  
Picosecond Laser Pulses

STUDY OF TRANSVERSE EFFECTS IN THE PRODUCTION OF X-RAYS WITH A FREE-ELECTRON LASER BASED ON AN OPTICAL UNDULATOR

2007 ◽  
Vol 22 (23) ◽  
pp. 4270-4279
Author(s):  
A. BACCI ◽  
C. MAROLI ◽  
V. PETRILLO ◽  
L. SERAFNI ◽  
M. FERRARIO
Keyword(s):  
Electron Beam ◽  
Free Electron ◽  
Free Electron Laser ◽  
Laser Energy ◽  
Laser Pulses ◽  
Collective Effects ◽  
Laser Source ◽  
X Rays ◽  
X Ray ◽  
Back Scattering

The interaction between high-brilliance electron beams and counter-propagating laser pulses produces X rays via Thomson back-scattering. If the laser source is long and intense enough, the electrons of the beam can bunch and a regime of collective effects can establish. In this case of dominating collective effects, the FEL instability can develop and the system behaves like a free-electron laser based on an optical undulator. Coherent X-rays can be irradiated, with a bandwidth very much thinner than that of the corresponding incoherent emission. The emittance of the electron beam and the distribution of the laser energy are the principal quantities that limit the growth of the X-ray signal. In this work we analyse with a 3-D code the transverse effects in the emission produced by a relativistic electron beam when it is under the action of an optical laser pulse and the X-ray spectra obtained. The scalings typical of the optical wiggler, characterized by very short gain lengths and overall time durations of the process make possible considerable emission also with emittance of the order of 1mm mrad.

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