Laser for wakefield plasma accelerator

The recent development of the technology to build tabletop high power (terawatt) short pulse (picosecond) lasers has enabled the realization of the wakefield accelerator. The characteristics of a Nd:glasses laser for use as the laser driver for a wakefield accelerator are described. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87312/2/301_1.pd

Emission and its back-reaction accompanying electron motion in relativistically strong and QED-strong pulsed laser fields

The emission from an electron in the field of a relativistically strong laser pulse is analyzed. At pulse intensities of J > 2 10^22 W/cm2 the emission from counter-propagating electrons is modified by the effects of Quantum ElectroDynamics (QED), as long as the electron energy is sufficiently high: E > 1 GeV. The radiation force experienced by an electron is for the first time derived from the QED principles and its applicability range is extended towards the QED-strong fields.Comment: 14 pages, 5 figures. Submitted to Phys.Rev.

Relativistic attosecond physics

A study, with particle-in-cell simulations, of relativistic nonlinear optics in the regime of tight focus and ultrashort pulse duration (the λ3λ3 regime) reveals that synchronized attosecond electromagnetic pulses [N. M. Naumova, J. A. Nees, I. V. Sokolov, B. Hou, and G. A. Mourou, Phys. Rev. Lett. 92, 063902 (2004)] and attosecond electron bunches [N. Naumova, I. Sokolov, J. Nees, A. Maksimchuk, V. Yanovsky, and G. Mourou, Phys. Rev. Lett. 93, 195003 (2004)] emerge efficiently from laser interaction with overdense plasmas. The λ3λ3 concept enables a more basic understanding and a more practical implementation of these phenomena because it provides spatial and temporal isolation. The synchronous generation of strong attosecond electromagnetic pulses and dense attosecond electron bunches provides a basis for relativistic attosecond optoelectronics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87762/2/056707_1.pd

Dependence of hard x-ray yield on laser pulse parameters in the wavelength-cubed regime

Conversion efficiency and electron temperature scaling laws are experimentally studied in the wavelength-cubed (λ3)(λ3) regime, where a single-wavelength focus allows low energy pulses incident on a Mo target to produce x rays with excellent efficiency and improved spatial coherence. Focused intensity is varied from 2×10162×1016 to 2×1018 W/cm2.2×1018W/cm2. Conversion efficiency and electron temperature are best described by a power law for energy scaling while an exponential law best describes the scaling of these parameters with pulse duration. © 2004 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69364/2/APPLAB-84-13-2259-1.pd

Quasimonoenergetic electron beams with relativistic energies and ultrashort duration from laser-solid interactions at 0.5 kHz

International audienceWe investigate the production of electron beams from the interaction of relativistically-intense laser pulses with a solid-density SiO2 target in a regime where the laser pulse energy is -mJ and the repetition rate -kHz. The electron beam spatial distribution and spectrum were investigated as a function of the plasma scale length, which was varied by deliberately introducing a moderate-intensity prepulse. At the optimum scale length of λ/2, the electrons are emitted in a collimated beam having a quasimonoenergetic distribution that peaked at -0.8MeV. A highly reproducible structure in the spatial distribution exhibits an evacuation of electrons along the laser specular direction and suggests that the electron beam duration is comparable to that of the laser pulse. Particle-in-cell simulations which are in good agreement with the experimental results offer insights on the acceleration mechanism by the laser field. © 2009 The American Physical Society

Dynamics of Emitting Electrons in Strong Electromagnetic Fields

We derive a modified non-perturbative Lorentz-Abraham-Dirac equation. It satisfies the proper conservation laws, particularly, it conserves the generalized momentum, the latter property eliminates the symmetry-breaking runaway solution. The equation allows a consistent calculation of the electron current, the radiation effect on the electron momentum, and the radiation itself, for a single electron or plasma electrons in strong electromagnetic fields. The equation is applied to a simulation of a strong laser pulse interaction with a plasma target. Some analytical solutions are also provided.Comment: The original form of this paper was submitted to Phys. Rev. Lett. on August 3, 2008. The current version of the paper is substantially extended and includes modifications resulting from points raised during the review proces

Roadmap on ultrafast optics

Contains fulltext : 166150.pdf (publisher's version ) (Closed access

Science and applications of the coherent amplifying network (CAN) laser

Accelerators are today in every walk of science and life [1]. High intensity lasers drive frontiers of contemporary science. Lasers in the TW and PW regime have the potential to replace conventional accelerators with the distinct advantage to be dramatically shorter by a factor of a thousand or more [2]. For instance, electrons are accelerated to few GeV over only few centimeters, representing three to fours orders of magnitude higher accelerating gradients than traditional RF-based accelerators can offer. The approach was proposed in 1979 [3], where a strong laser pulse [4], moving in a plasma creates a wake in which electrons are trapped and violently accelerated. In addition, under ultra high intensity, high energy protons over 100 MeV have been demonstrated as well as high energy radiation greater that MeV [5]. Key to laser-driven accelerators, ion, X-Ray, or Gamma-Ray production are ultra high peak power lasers at the petawatt level [6]. However, current petawatt laser exhibits low repetition rates (state-of-the-art is about 1 Hz) due to thermo-optical character in their gain medium, resulting in low average powers in the 50 W range. In addition, a rather poor wall-plug efficiency (electrical power to optical power) of 10−3% avoids any scaling perspectives. Hence, state-of-the-art high peak power laser system cannot pretend to be tomorrow's replacement to conventional RF Technology –a new class of ultrafast lasers is urgently needed. Under the ICFA-ICUIL [2] initiative, laser experts in the field of particle acceleration and high intensity lasers defined target parameters of a future laser system should deliver to pave the way for a new kind of accelerator technology revolutionizing fundamental science and applications. The following laser parameters are envisaged for what could be a future linear e–e+ collider: peak power in the PW regime, defined by a 10's of Joules of pulse energy and an ultrashort pulse duration below 50 fs, in combination with an unparalleled average power exceeding 100 kW even exceeding the megawatt level, implying repetition rates of >10 kHz. These extreme parameters should be contained in a beam of excellent spatial quality, featuring outstanding temporal stability and temporal contrast. An excellent wall-plug efficiency of >30% is an essential condition that such average powers are realized in a cost effective, economic and compact way. Overall, any known laser technology known today faces severe issues, with current performance orders of magnitude below these target parameters. Inspired by these ground-breaking challenges under the Eu leadership, the International Coherent Amplification Network (ICAN) group was formed. It combines the complementary expertise of science authorities in the field of high performance fiber amplifiers, theoretical and applied optics of optical systems and finally ultra high intensity lasers. ICAN aspired to study the fundamentals of interferometric amplification i.e. spatially separated amplification followed by coherent addition, of ultrashort laser pulses as the underlying concept of a breakthrough in laser physics. In detail ICAN has studied: 1) average/peak power and efficiency limits of coherently combined ultrafast laser systems 2) synchronization, spatial and temporal recombination of a large number of fibers amplifiers 3) temporal and spatial beam quality, combining efficiency of coherent addition, amplitude and phase stability as a function of the number of fibers and their individual performance 4) reduction of pulse duration and manipulation of pulse shape

Optique non-linéaire à haute intensité (Compression d'impulsions laser Interaction laser-plasma)

Cette thèse principalement théorique se situe dans le cadre de l'utilisation du laser de la Salle Noire du LOA, qui fournit des impulsions ultracourtes (2 cycles optiques) et énergétiques (1mJ) à 1kHz, stabilisées en CEP, pour générer des harmoniques sur cible solide. D'une part, pour profiter pleinement des ressources du laser, j'ai développé un code de simulation de propagation dans une fibre creuse qui, associé à une analyse expérimentale, a permis de repousser la limite en énergie de cette technique de compression. J'ai d'autre part utilisé des simulations PIC et j'ai développé un modèle de simulation de l'émission CWE pour quantifier sa dépendance aux conditions laser et plasma. Ce travail a servi premièrement à expliquer la variation expérimentale du spectre CWE à la CEP de l'impulsion laser. Deuxièmement, à partir d'une étude paramétrique expérimentale des spectres CWE, de remonter à des informations sur le plasma tels que le gradient de densité et la température électroniqueThis mainly theoretical PhD thesis has been done in the framework of high-order harmonics generation on solid targets using 1mJ ultrashort laser pulses (2 optical cycles) at high repetition rate (1kHz), CEP-stabilized. On the one hand, in order to fully use the laser source, I developed a simulation code of hollow-core fiber propagation. The results of this code, associated with an experimental study, allowed to push the energy limitation of this compression technique. On the other hand, I used PIC simulation and I developed a simulation model of CWE in order to quantify its dependence to the laser and plasma parameters. This work first helped to explain the CWE spectrum changes with pulse CEP. Second, by comparing theoretical results with an experimental parametric study, it provided information about the plasma conditions such as density gradient and electronic temperature.PALAISEAU-Polytechnique (914772301) / SudocSudocFranceF

The Time Integrated Far Field for Maxwell’s and D’Alembert’s Equations

Abstract. For x large consider the electric field, E(t, x) and its temporal Fourier Transform, Ê(ω, x). The D.C. component Ê(0, x) is equal to the time integral of the electric field. Experimentally, one observes that the D.C. component is negligible compared to the field. In this paper we show that this is true in the far field for all solutions of Maxwell’s equations. It is not true for typical solutions of the scalar wave equation. The difference is explained by the fact that though each component of the field satisfies the scalar wave equation, the spatial integral of ∂tE(t, x) vanishes identically. For the scalar wave equation the spatial integral of ∂tu(t, x) need not vanish. This conserved quantity gives the leading contribution to the time integrated far field. We also give explit formulas for the far field behavior of the time integrals of the intensity