Evidence of photon acceleration by laser wake fields

Abstract

Photon acceleration is the phenomenon whereby a light wave changes color when propagating through a medium whose index of refraction changes in time. This concept can be used to describe the spectral changes experienced by electromagnetic waves when they propagate in spatially and temporally varying plasmas. In this paper the detection of a large-amplitude laser-driven wake field is reported for the first time, demonstrating photon acceleration. Several features characteristic of photon acceleration in wake fields, such as splitting of the main spectral peak and asymmetries between the blueshift and redshift for large shifts, have been observed. The experiment is modeled using both a novel photon-kinetic code and a three-dimensional particle-in-cell code. In addition to the wide-ranging applications in the field of compact particle accelerators, the concept of wave kinetics can be applied to understanding phenomena in nonlinear optics, space physics, and fusion energy research

Limits of validity of photon-in-cell simulation techniques

“…[15][16][17][18] All of these use the photon-in-cell algorithm described below. The numerical implementation of Eq.…”

Maxwell and the classical wave particle dualism

“…In this sense, they behave as any other particle. This occurs, for instance, in a plasma, where relativistic electron plasma waves (produced by an intense laser pulse or by a relativistic electron bunch) can trap and accelerate photons belonging to another test pulse or to the driver pulse itself (Murphy 2006). This can also occur in a dielectric crystal, where infrared or visible photons can be accelerated by terahertz polaritons (Mendonça 2006).…”

Particle acceleration by electromagnetic waves

“…The study of plasma accelerators has opened up a coherent description of both electron and photon accelerations. Recent experiments (Murphy et al 2006) have demonstrated the effectiveness of photon acceleration by plasma waves in laser wakefield experiments. We can use the symmetry to investigate electrons as a moving mirror to photons or vice versa giving rise to the concept of a photon mirror.…”

“…The photon Landau damping is described by the kinetic effects retained in the Klimontovich equation. The process is equivalent to photon acceleration (Murphy et al 2006) where a photon pulse increases in energy through the interaction with a large-amplitude plasma wave. This is analogous to electron acceleration by the plasma wave in plasma accelerators.…”