Optimising laser-driven electron acceleration

In particular, the authors calculate the optimal values of the laser beam required to achieve maximum electron energy for different laser power levels. They observe that tuning certain aspects of a laser such as its beam waist -- the point at which a laser beam has its minimum radius -- can favourably increase the maximum acceleration of electrons in a vacuum for both linearly and circularly polarised lasers.

As may be expected, Molnar and colleagues find that the net energy of the electrons, and thus their acceleration, is raised with increased laser power for beams with optimal beam waists. The paper describes an average energy gain in electrons of a few MeV in full pulse interactions, in which the highest energy electrons possess is roughly 160 MeV. In other cases such as half-pulse interactions, however, the authors say that these energy gains are almost an order of magnitude greater -- reaching up to 1 GeV.

In terms of future research, the paper puts forward other potential directions. For example, the researchers suggest a study with a focus on direct laser acceleration with higher Laguerre Gaussian modes -- circularly symmetric beam profiles or lasers with cavities that are cylindrically symmetric -- should follow the current paper.