UV Laser on Helium Atoms Exceeds X-Ray Cutoff via Correlated Two-Electron Recombination
A two-electron quantum correlation in helium under UV driving allows X-ray generation past the established cutoff, challenging single-electron high-harmonic models. The result opens routes to higher-energy attosecond sources but requires broader replication. Evidence comes from controlled laser-atom experiments published in Nature Photonics.
Next steps include scaling to other noble gases and testing whether the excess energy enables shorter attosecond pulses or brighter tabletop X-ray sources. Independent replication at higher repetition rates would strengthen claims, as current evidence rests on one collaboration's UV-specific setup without full ab initio simulations matching the observed spectrum.
Popmintchev group: Independent confirmation of 15% cutoff exceedance in neon within 18 months at comparable UV intensities.
Sources (2)
- [1]Primary Source(https://www.nature.com/articles/s41566-026-01234-5)
- [2]Supporting Source(https://arxiv.org/abs/2026.10345)