Mono-energetic GeV electrons from ionization in a radially polarized laser beam (original) (raw)

Electron scattering and acceleration by a tightly focused laser beam

Physical Review Special Topics - Accelerators and Beams, 2002

By numerically solving the relativistic equations of motion of a single electron in laser fields modeled by those of a Gaussian beam, we demonstrate electron capture by, reflection from, and transmission through the beam. In modeling the fields, terms of order up to 5 , where is the diffraction angle, are retained. All cases of capture are accompanied by energy gain that may reach a few GeV, from fields of present-day intensities. Reflection and transmission, on the other hand, result sometimes in no gain or even in a loss of energy. It is shown that a laboratory static magnetic field may be used to eject a captured electron, a process that sometimes results in even more energy gain. For example, a 2.5 T uniform magnetic field suffices to eject a 3.633 MeV electron injected at 6 to the axis of a linearly polarized beam of a 10 PW power output and aimed at a point near the focus. Such an electron gains 1128 MeV from the laser field alone. However, it emerges with a 1230 MeV net energy gain under the additional action of the small magnetic field.

Field Polarization Effect On Electron Dynamics In Strong Laser Field

AIP Conference Proceedings

In this paper we present a comparison between the effects on electron dynamics by a linearly polarized and a circularly polarized field of an intense laser beam. Special attention is given to the vacuum laser acceleration scheme, also known as capture and acceleration scenario (CAS). It has been found that CAS phenomenon can occur in both polarized fields but there are differences. The CAS of a circularly polarized field exhibits axisymmetric feature, whereas CAS of a linearly polarized field can only be observed when electrons are injected nearly along the polarization plane. Given the same laser parameters (intensity, beam width), the maximum energy gained by the electrons from linearly polarized field is higher than that from circularly polarized field. Physical explanations based on the space distributions of the field amplitudes are described. We hope this study provides significant help to those designing experimental setup to verify CAS as well as to those developing laser accelerators of the future.

Electron dynamics in circularly-polarized laser and uniform electric fields: acceleration in vacuum

Physics Letters A, 2001

We solve exactly analytically the relativistic equation of motion of a single electron injected initially at an angle to the direction of propagation of a circularly-polarized plane-wave laser field, of arbitrary intensity, and a uniform electric field. It is shown, in principle, that the electron may be accelerated to high energies in this environment.  2001 Elsevier Science B.V. All rights reserved. 52.40.Nk; 42.50.Vk; 52.75.Di 0375-9601/01/$ -see front matter  2001 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 5 -9 6 0 1 ( 0 1 ) 0 0 2 2 8 -6

Electron acceleration in combined laser and uniform electric fields

Journal of Physics A: Mathematical and General, 2001

An exact analytical solution for the equation of motion of a single relativistic electron, injected initially at some angle ξ to the propagation direction of a linearly polarized plane-wave laser field of arbitrary intensity and a uniform electric field oriented anti-parallel to the laser propagation direction, is developed. The solution is then used to investigate the issue of electron acceleration to high energies in the prescribed fields. It is found that, in principle, an electron may be accelerated from rest or motion to several hundred GeV, if the uniform electric field strength E s approaches a critical value E c s = (mωc)/(2πNe), where m and e are the mass and charge of the electron, c is the speed of light in vacuum, N is the number of field cycles in the pulse andω is the Doppler-shifted frequency of the laser field as seen by the electron upon initial injection. The radiation losses during acceleration are shown to be negligible and the spectrum of the radiation emitted along the initial direction of motion (parallel injection) of the electron is shown to consist mostly of the fundamental laser frequency.

Relativistic electron acceleration in focused laser fields after above-threshold ionization

Physical Review E, 2003

Electrons produced as a result of above-threshold ionization of high-Z atoms can be accelerated by currently producible laser pulses up to GeV energies, as shown recently by Hu and Starace ͓Phys. Rev. Lett. 88, 245003 ͑2002͔͒. To describe electron acceleration by general focused laser fields, we employ an analytical model based on a Hamiltonian, fully relativistic, ponderomotive approach. Though the above-threshold ionization represents an abrupt process compared to laser oscillations, the ponderomotive approach can still adequately predict the resulting energy gain if the proper initial conditions are introduced for the particle drift following the ionization event. Analytical expressions for electron energy gain are derived and the applicability conditions of the ponderomotive formulation are studied both analytically and numerically. The theoretical predictions are supported by numerical computations.

Electron Acceleration by a Tightly Focused Laser Beam

Physical Review Letters, 2002

State-of-the-art petawatt laser beams may be focused down to few-micron spot sizes and can produce violent electron acceleration as a result of the extremely intense and asymmetric fields. Classical fifthorder calculations in the diffraction angle show that electrons, injected sideways into the tightly focused laser beam, get captured and gain energy in the GeV regime. We point out the most favorable points of injection away from the focus, along with an efficient means of extracting the energetic electron with a static magnetic field.

Electron acceleration from rest in vacuum by an axicon Gaussian laser beam

Physical Review A, 2006

We employ the lowest-order radially polarized axicon fields of a Gaussian laser beam to demonstrate that electrons may be accelerated from rest in vacuum to a few GeV. Petawatt power laser beams focused onto micron-size focal spots result in multi-TeV/m electron energy gradients.

Direct Electron Acceleration with Radially Polarized Laser Beams

Applied Sciences, 2013

In the past years, there has been a growing interest in innovative applications of radially polarized laser beams. Among them, the particular field of laser-driven electron acceleration has received much attention. Recent developments in high-power infrared laser sources at the INRS Advanced Laser Light Source (Varennes, Qc, Canada) allowed the experimental observation of a quasi-monoenergetic 23-keV electron beam produced by a radially polarized laser pulse tightly focused into a low density gas. Theoretical analyses suggest that the production of collimated attosecond electron pulses is within reach of the actual technology. Such an ultrashort electron pulse source would be a unique tool for fundamental and applied research. In this paper, we propose an overview of this emerging topic and expose some of the challenges to meet in the future.