Acceleration-field calculation for a structure-based laser-driven linear accelerator

A laser-driven particle accelerator, scaled to optical wavelengths, has a feature size many orders  of magnitude smaller than a radio-frequency accelerator. However, similar to a radio-frequency accelerator, a laser-driven accelerator cell may have apertures to transmit electrons. We numerically calculate the acceleration field for a cylindrically focused, crossed-laser-beam linear accelerator with the presence of electron transit apertures. A 4-μm-width electron aperture decreases electron energy gain by 17%, and a 6-μm-width aperture decreases energy gain by 34% relative to a structure without apertures.