Focussing effects in laser-electron Thomson scattering

Abstract

We study the effects of laser pulse focussing on the spectral properties of Thomson scattered radiation. Modelling the laser as a paraxial beam we find that, in all but the most extreme cases of focussing, the temporal envelope has a much bigger effect on the spectrum than the focussing itself. For the case of ultra-short pulses, where the paraxial model is no longer valid, we adopt a sub-cycle vector beam description of the field. It is found that the emission harmonics are blue shifted and broaden out in frequency space as the pulse becomes shorter. Additionally the carrier envelope phase becomes important, resulting in an angular asymmetry in the spectrum. We then use the same model to study the effects of focussing beyond the limit where the paraxial expansion is valid. It is found that fields focussed to sub-wavelength spot sizes produce spectra that are qualitatively similar to those from sub-cycle pulses due to the shortening of the pulse with focussing. Finally, we study high-intensity fields and find that, in general, the focussing makes negligible difference to the spectra in the regime of radiation reaction.

14 pages, 17 figures

References in corpus (10)

• Ultra-high brilliance multi-MeV $\gamma$-ray beam from non-linear Thomson scattering
• Radiation Reaction Effects on Radiation Pressure Acceleration
• Nonlinear Compton scattering in ultra-short laser pulses
• Non-Linear Compton Scattering of Ultrashort and Ultraintense Laser Pulses
• Testing numerical implementations of strong field electrodynamics
• Aspects of electromagnetic radiation reaction in strong fields
• Analytical tools for investigating strong-field QED processes in tightly focused laser fields
• Robust signatures of quantum radiation reaction in focused ultrashort laser pulses
• Covariant Worldline Numerics for Charge Motion with Radiation Reaction
• Magnetic mirror cavities as THz radiation sources and a means of quantifying radiation friction

Cited by in corpus (6)

• Nonlinear Breit-Wheeler pair production in a tightly focused laser beam
• Exact classical and quantum dynamics in background electromagnetic fields
• First-order strong-field QED processes in a tightly focused laser beam
• Optimizing Laser Pulses for Narrowband Inverse Compton Sources in the High-Intensity Regime
• Laser Pulsing in Linear Compton Scattering
• Coherent quantum enhancement of pair production in the null domain