Electron laser acceleration in vacuum by a quadratically chirped laser pulse

Single MeV electrons subjected in vacuum to single high-intensity quadratically-chirped laser pulses are shown to gain multi-GeV energies. The laser pulses are modeled by finite-duration trapezoidal and $\cos^2$ pulse-shapes and the equations of motion are solved numerically. It is found that, typically, the maximum energy gain from interaction with a quadratic chirp is about half of what would be gained from a linear chirp.