99 research outputs found
Controlling the ellipticity of attosecond pulses produced by laser irradiation of overdense plasmas
The interaction of high-intensity laser pulses and solid targets provides a
promising way to create compact, tunable and bright XUV attosecond sources that
can become a unique tool for a variety of applications. However, it is
important to control the polarization state of this XUV radiation, and to do so
in the most efficient regime of generation. Using the relativistic electronic
spring (RES) model and particle-in-cell (PIC) simulations, we show that the
polarization state of the generated attosecond pulses can be tuned in a wide
range of parameters by adjusting the polarization and angle of incidence of the
laser radiation. In particular, we demonstrate the possibility of producing
circularly polarized attosecond pulses in a wide variety of setups.Comment: 6 pages, 3 figure
Prospects and limitations of wakefield acceleration in solids
Advances in the generation of relativistic intensity pulses with wavelengths
in the X-ray regime, through high harmonic generation from near-critical
plasmas, opens up the possibility of X-ray driven wakefield acceleration. The
similarity scaling laws for laser plasma interaction suggest that X-rays can
drive wakefields in solid materials providing TeV/cm gradients, resulting in
electron and photon beams of extremely short duration. However, the wavelength
reduction enhances the quantum parameter , hence opening the question of
the role of non-scalable physics, e.g., the effects of radiation reaction.
Using three dimensional Particle-In-Cell simulations incorporating QED effects,
we show that for the wavelength nm and relativistic amplitudes
-100, similarity scaling holds to a high degree, combined with
operation already at moderate , leading to photon
emissions with energies comparable to the electron energies. Contrasting to the
generation of photons with high energies, the reduced frequency of photon
emission at X-ray wavelengths (compared to at optical wavelengths) leads to a
reduction of the amount of energy that is removed from the electron population
through radiation reaction. Furthermore, as the emission frequency approaches
the laser frequency, the importance of radiation reaction trapping as a
depletion mechanism is reduced, compared to at optical wavelengths for
leading to similar .Comment: 9 pages, 7 figure
Quantum optical signatures in strong-field laser physics: Infrared photon counting in high-order-harmonic generation
We analytically describe the strong-field light-electron interaction using a
quantized coherent laser state with arbitrary photon number. We obtain a
light-electron wave function which is a closed-form solution of the
time-dependent Schrodinger equation (TDSE). This wave function provides
information about the quantum optical features of the interaction not
accessible by semi-classical theories. With this approach we can reveal the
quantum optical properties of high harmonic generation (HHG) process in gases
by measuring the photon statistics of the transmitted infrared (IR) laser
radiation. This work can lead to novel experiments in high-resolution
spectroscopy in extreme-ultraviolet (XUV) and attosecond science without the
need to measure the XUV light, while it can pave the way for the development of
intense non-classical light sources.Comment: 9 pages, 4 figure
Multi-Cascade Proton Acceleration by Superintense Laser Pulse in the Regime of Relativistically Induced Slab Transparency
A regime of multi-cascade proton acceleration in the interaction of
W/cm laser pulse with a structured target is proposed.
The regime is based on the electron charge displacement under the action of
laser ponderomotive force and on the effect of relativistically induced slab
transparency which allows to realize idea of multi-cascade acceleration. It is
shown that a target comprising several properly spaced apart thin foils can
optimize the acceleration process and give at the output quasi-monoenergetic
beams of protons with energies up to hundreds of MeV with energy spread of just
few percent.Comment: 5 pages with 4 figure
Ultrarelativistic nanoplasmonics as a new route towards extreme intensity attosecond pulses
The generation of ultra-strong attosecond pulses through laser-plasma
interactions offers the opportunity to surpass the intensity of any known
laboratory radiation source, giving rise to new experimental possibilities,
such as quantum electrodynamical tests and matter probing at extremely short
scales. Here we demonstrate that a laser irradiated plasma surface can act as
an efficient converter from the femto- to the attosecond range, giving a
dramatic rise in pulse intensity. Although seemingly similar schemes have been
presented in the literature, the present setup deviates significantly from
previous attempts. We present a new model describing the nonlinear process of
relativistic laser-plasma interaction. This model, which is applicable to a
multitude of phenomena, is shown to be in excellent agreement with
particle-in-cell simulations. We provide, through our model, the necessary
details for an experiment to be performed. The possibility to reach intensities
above 10^26 W/cm^2, using upcoming 10 petawatt laser sources, is demonstrated.Comment: 15 pages, 5 figure
Anomalous Radiative Trapping in Laser Fields of Extreme Intensity
We demonstrate that charged particles in a sufficiently intense standing wave
are compressed toward, and oscillate synchronously at, the maxima of the
electric field. This unusual trapping behaviour, which we call 'anomalous
radiative trapping' (ART), opens up new possibilities for the generation of
radiation and particle beams, both of which are high-energy, directed and
collimated. ART also provides a mechanism for particle control in
high-intensity QED experiments.Comment: 5 pages, 5 pdf figures. Version 2: extended discussion of particle
trajectories, references adde
Physics of the laser-plasma interface in the relativistic regime of interaction
The reflection of intense laser radiation from solids appears as a result of
relativistic dynamics of the electrons driven by both incoming and
self-generated electromagnetic fields at the periphery of the emerging dense
plasma. In the case of highly-relativistic motion, electrons tend to form a
thin oscillating layer, which makes it possible to model the interaction and
obtain the temporal structure of the reflected radiation. The modelling reveals
the possibility and conditions for producing singularly intense and short XUV
bursts of radiation, which are interesting for many applications. However, the
intensity and duration of the XUV bursts, as well as the high-energy end of the
harmonic spectrum, depends on the thickness of the layer and its internal
structure which are not assessed by such macroscopic modelling. Here we analyse
the microscopic physics of this layer and clarify how its parameters are bound
and how this controls outlined properties of XUV bursts.Comment: 9 pages, 5 figure
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