Ponderomotive Laser Acceleration and Focusing in Vacuum for Generation of Attosecond Electron Bunches

A novel approach for the generation of ultrabright attosecond electron bunches is proposed, based on acceleration in vacuum, by a short laser pulse. The laser-pulse profile is tailored such that the electrons are both focused and accelerated by the ponderomotive force of the light. Using time-averaged equations of motion, analytical criteria for optimal regime of acceleration are found. It is shown that for realistic laser parameters, a beam with up to ${10}^6$ particles and normalized transverse and longitudinal emittances $<{10}^{-8\mathrm{}}\mathrm{m}$ can be produced.