Anomalous Relativistic Emission from Self-Modulated Plasma Mirrors

The interaction of relativistically intense laser pulse with a plasma mirror produces harmonics of the incident frequency co-propagating in the direction of specular reflection due to the plasma mirror surface oscillating with velocity close to the speed of light. This mechanism has shown its potential for realization of a bright source of extreme ultraviolet radiation and attosecond pulses. Here, we reveal an unexpected transition of this well-known process into a new regime of efficient extreme ultraviolet radiation generation. A novel mechanism of relativistic emission of radiation from plasma mirrors is identified with an extraordinary property that instead of following specular reflection, the radiation is emitted in the direction along the plasma mirror surface. With analytical calculations and numerical particle-in-cell simulations, we show that this radiation originates from laser-driven non-linear oscillations of relativistic electron nanobunches that are generated by a plasma surface instability and propagate along the plasma mirror surface.Comment: 6 pages, 3 figure

16th International Conference on X-Ray Lasers

These proceedings gather a selection of invited and contributed papers presented during the 16th International Conference on X-Ray Lasers (ICXRL 2018), held in Prague, Czech Republic, from 7 to 12 October 2018. The conference is part of an ongoing series dedicated to recent developments in the science and technology of X-ray lasers and other coherent X-ray sources, with an additional focus on supporting technologies, instrumentation and applications. The book highlights advances in a wide range of fields including laser and discharge-pumped plasma X-ray lasers, the injection and seeding of X-ray amplifiers, high-order harmonic generation and ultrafast phenomena, X-ray free electron lasers, novel schemes for (in)coherent XUV, X-ray and γ-ray generation, XUV and X-ray imaging, optics and metrology, X-rays and γ-rays for fundamental science, the practical implementation of X-ray lasers, XFELs and super-intense lasers, and the applications and industrial uses of X-ray lasers

Generation of intense magnetic wakes by relativistic laser pulses in plasma

Abstract The emergence of petawatt lasers focused to relativistic intensities enables all-optical laboratory generation of intense magnetic fields in plasmas, which are of great interest due to their ubiquity in astrophysical phenomena. In this work, we study generation of spatially extended and long-lived intense magnetic fields. We show that such magnetic fields, scaling up to the gigagauss range, can be generated by interaction of petawatt laser pulses with relativistically underdense plasma. With three-dimensional particle-in-cell simulations we investigate generation of magnetic fields with strengths up to $$10^{10}$$ 10 10 G and perform a large multi-parametric study of magnetic field in dependence on dimensionless laser amplitude $$a_{0}$$ a 0 and normalized plasma density $$n_{e}/n_{c}$$ n e / n c . The numerical results yield scaling laws that closely follow derived analytical result $$B \propto \sqrt{a_{0}n_{e}/n_{c}}$$ B ∝ a 0 n e / n c , and further show a close match with previous experimental works. Furthermore, we show in three-dimensional geometry that the decay of the magnetic wake is governed by current filament bending instability, which develops similarly to von Kármán vortex street in its nonlinear stage

Multi-Lane Mirror for Broadband Applications of the Betatron X-ray Source

A new generation of small-scale ultrafast X-ray sources is rapidly emerging. Laser-driven betatron radiation represents an important class of such ultrafast X-ray sources. With the sources driving towards maturity, many important applications in material and biological sciences are expected to be carried out. While the last decade mainly focused on the optimization of the source properties, the development of such sources into user-oriented beamlines in order to explore the potential applications has recently taken off and is expected to grow rapidly. An important aspect in the realization of such beamlines will be the implementation of proper X-ray optics. Here, we present the design of a multi-lane X-ray mirror as a versatile focusing device covering a wide spectral range of betatron X-rays. The expected photon flux in the focal plane of such optics was also estimated through geometrical simulations

X-ray phase contrast imaging of biological samples using a betatron X-ray source generated in a laser wakefield accelerator

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Measurement of a subpicosecond coherence time in a quasi-steady-state XUV laser

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Multiscale modelling of HHG and its applications for phase-matching optimisation

International audienceWe present a multiscale approach to model high-harmonic generation in gaseous media. Such a treatment is indispensable for a quantitive description of phenomena emerging from the interplay of the microscopic response of a single microscopic emitter, and the macroscopic profile of the driving beam propagating in a generating medium. In particular, we address phase-matching controlled by pre-ionising the medium

New probing techniques of radiative shocks

International audienceRadiative shock waves propagating in xenon at a low pressure have been produced using 60 joules of iodine laser (λ = 1.315 μm) at PALS center. The shocks have been probed by XUV imaging using a Zn X-raylaser (λ = 21 nm) generated with a 20-ns delay after the shock creating pulse. Auxiliary high-speed silicon diodes allowed performing space- and time-resolved measurement of plasma self-emission in the visible and XUV. The results show the generation of a shock wave propagating at 60 km/s preceded by a radiative precursor. This demonstrates the feasibility of radiative shock generation using high power infrared lasers and the use of XRL backlighting as a suitable diagnostic for shock imaging