Laser-triggered fast charge-separation field generates a strong surface current and wave

Transient surface electromagnetic fields triggered by a super-short laser pulse through ultrafast generation of a charge-separation field at a high-conductivity target have been studied. Both the analytic theory applicable to the near-field problem and the finite-difference time-domain simulations clearly manifest distinctive features of the proposed mechanism, which is associated with fast electric polarization of a high-conductivity target by rapidly switching on a charge-separation field when an ultrashort laser pulse quickly pushes the target electrons out to a vacuum. This mechanism is well suited for the current trend in creating lasers with a record short pulse duration for laser-plasma interactions.