Physicists have used lasers to increase the amount of energy that electrons gain per metre by more than two orders of magnitude compared with traditional accelerators.

Conventional colliders can accelerate particles to much greater energies, but over many kilometres. Wim Leemans at Lawrence Berkeley National Laboratory in California and his colleagues used extremely intense laser pulses and an ionized gas to boost electrons over much smaller distances.

By guiding the pulses through channels in the plasma, the researchers generated strong electric fields that increased injected electrons to 4.2 gigaelectronvolts — the highest energy ever achieved in a laser-based system — over just 9 centimetres.

The authors say that the technique could be used to make smaller high-energy linear accelerators, and to create table-top systems that use X-rays emitted by electrons to probe materials.

Phys. Rev. Lett. 113, 245002 (2014)