If you mix a little antimatter into a laser beam, it makes the whole thing ten times more powerful.
March 17, 2026
Original Paper
Pair beams unlock beyond-terawatt attosecond free-electron laser pulses
arXiv · 2603.15407
The Takeaway
In ultra-powerful X-ray lasers, the high concentration of electrons usually pushes the beam apart due to electrical repulsion. By adding positrons—the antimatter twin of the electron—the charges cancel out, allowing the beam to stay focused and reach record-breaking 'terawatt' power levels.
From the abstract
Free-electron lasers (FELs) generate the brightest coherent X-ray pulses available, enabling atomic-resolution and femtosecond-timescale studies across physics, chemistry, and biology. Realising their full potential at extreme peak powers and attosecond pulse durations critically depends on sustaining coherent gain across the full bunch length. Yet, the quasi-static longitudinal space-charge field in the ultrahigh-current regime imprints a slice-dependent energy detuning that quenches gain growt