Ultrashort laser pulses and ultrashort electron bunches generated in relativistic laser-plasma interaction

Abstract

An experimental study of the interaction of ultrashort laser pulses with underdense plasmas in the relativistic regime is presented. A parameter regime of particular interest was found: the so-called bubble regime. In this regime, the laser pulse is focused to relativistic intensities and its pulse duration is comparable to or shorter than the plasma period. A wealth of physical phenomena occurs for such physical parameters. These phenomena have multiple signatures which have been investigated experimentally: (i) the generation of a high quality electron beam (high energy, very collimated, quasimonoenergetic energy distribution); (ii) the laser pulse temporal shortening in nonlinear plasma waves. In addition, experimental results suggest that the electron beam produced in this way has temporal structures shorter than 50fs.

Demonstration of the ultrafast nature of laser produced betatron radiation

“…Indeed, x-ray and electrons pulses have quasisimilar durations. Indirect measurement of the laser-plasma accelerated electron bunch have been performed using different techniques: Sub-100 fs ͑full width͒ wakefield electron bunch duration has been estimated by the measurement of terahertz radiation 17,18 ͑duration Ͻ50 fs͒, electro-optic sampling, or from the characterization of the electron bunch profiles 19 ͑duration Ͻ25 fs͒ and electron spectrum 20 ͑duration Ͻ10 fs͒. A betatron x-ray pulse duration on the order of Ͻ100 fs is therefore supported by the duration of electron bunch obtained previously.…”

Control of Laser Plasma Based Accelerators up to 1 GeV

“…The laser pulse was hence long enough to suffer from longitudinal modulations. Laser pulse compression in plasma waves was reported with similar laser plasma parameters [196]. In Ref.…”

“…It is clear that both the input laser intensity and the total energy in the laser pulse affects injection process. For the total energy to play a critical role in the injection, the evolution of laser during the propagation in the plasma channel, especially pulse compression seems to be critical [196]. This input intensity a 0 0.45 had been believed to give no self-injection in sm-LWFA.…”

“…In Ref. [196], the laser pulse with ∼ 38 fs was focused onto a 3 mm length helium gas jet target, producing focused intensity of…”

Physics of Quasi-Monoenergetic Laser-Plasma Acceleration of Electrons in the Blowout Regime

“…These new instruments, accessible to a large community of researchers, revolutionized experiments in relativistic nonlinear optics (Mourou et al, 2006), and enabled the compact design of plasma-based particle accelerators (Esarey et al, 2009;Tajima & Dawson, 1979). Owing to continuous improvements in laser systems and gas target technology (Semushin & Malka, 2001;Spence & Hooker, 2001), stable generation of well-collimated, quasi-monoenergetic, hundred-megaelectronvolt (MeV)-scale electron beams from millimeter to centimeter-length plasmas has become experimentally routine (Brunetti et al, 2010;Faure et al, 2006;Hafz et al, 2008;Leemans et al, 2006;Maksimchuk et al, 2007;Malka et al, 2009;Mangles et al, 2007;Osterhoff et al, 2008). These beams have been used for a broad range of technical and medical physics applications -γ-ray radiography for material science Ramanathan et al, 2010), testing of radiation resistivity of electronic components used in harsh radiation environments (Hidding et al, 2011), efficient on-site production of radioisotopes (Leemans et al, 2001;Reed et al, 2007), and radiotherapy with tunable, high-energy electrons (DesRosiers et al, 2000;Glinec et al, 2006;Kainz et al, 2004).…”