Description
The behavior of a relativistic quasi-neutral electron-positron beam and the corresponding enhancement of coherent extreme ultraviolet (XUV) light emission are investigated by examining the optical free-electron laser (OFEL) setup, which employs a laser pulse in place of a conventional undulator. A key characteristic of the lasing mechanism in a free-electron laser is microbunching, which leads to the concentration of beam charges into slices shorter than the radiation wavelength, thereby enhancing coherent radiation. We investigated this microbunching property and coherent emission in OFELs where a quasi-neutral bunch, rather than an electron-only bunch, is utilized [1]. We demonstrated that the inherent stability of an electron-positron beam mitigates Coulomb expansion and renders it a promising alternative source of coherent light in the XUV domain, in the form of few-attosecond pulses [1]. This process occurs over a sub-millimeter length scale, enabling the development of ultra-compact light sources that could be employed in natural sciences and industry.
[1] M. J. Quin, A. Di Piazza, C. Erciyes, C. H. Keitel, M. Tamburini, Broadband coherent XUV light from e−/e+ microbunching in an intense laser pulse, arXiv:2411.17631
