Recently researchers have successfully accelerated electrons using laser pulses [1]. This achievement is far-reaching and will have immediate practical consequences; including  methods for building less expensive and smaller devices for medicine and materials science applications.  The new method capitalizes on our ability to implement techniques based on commercial near-infrared laser with greater efficiency then any pre-existing technology.

Behind all of this lies a simple idea. A particle’s velocity can be boosted through the interaction between its charge and the electric field component parallel to the particle beam line. Furthermore optimal acceleration conditions, which are experimentally more challenging to meet, dictate that the phase velocity of the accelerating field should always be tuned to the velocity of the relativistic particle.

In this experiment scientist used a micro-fabricated dielectric structure of two gratings (longitudinal cross-section resembles two opposing combs with some space in-between for the electrons to pass through). By preparing the right period for the gratings it was possible to get the diffraction modes of the incident laser pulse to form inside the structure and match the phase resonance conditions.

First results seem to be very promising. This new kind of accelerator offers electron acceleration of 250 MeV/m whereas the standard linear accelerator works at 30 MeV/m. Discoveries utilizing common tools, which promise better solution for practical applications, are always important.

[1] E. A. Peralta et al., Nature, 27 Sept 2013 (10.1038/nature12664)