Experimental Demonstration of Directional and Collimated Electron Acceleration with Hollow Laguerre-Gaussian Lasers.

We report the first experimental demonstration of directional and collimated electron acceleration in the direct laser acceleration regime using a relativistic hollow Laguerre-Gaussian (LG) laser. Electrons are confined within the hollow field distribution along the reflected laser direction, producing a collimated beam and overcoming the dispersed characteristic of Gaussian-laser-driven electrons. In particular, the left-circularly polarized LG laser generates a unique longitudinal resonant electric field on the axis, which, combined with transverse confinement, forms a stable acceleration structure. This leads to higher electron energies with improved stability and collimation compared with right-circularly polarized LG cases. The demonstrated LG-laser-driven collimating mechanism extends conventional direct laser acceleration into a stable and efficient regime, opening opportunities for particle collimation, high-flux particle sources, and coherent radiation generation in relativistic regimes.