Ultrashort laser-pulse-driven currents in conductors: one-dimensional model for local excitation in the single-electron picture with quadratic dispersion

The response of conduction-band electrons to a local, pulse-like external excitation is investigated. The charge density wave packets that emerge as a consequence of the excitation leave the interaction region with a speed close to the initial state’s band velocity, but there are also oscillations with essentially the same frequency as that of the laser field. As a good estimation, the excitation can also be considered as a localized, time-dependent ponderomotive potential, leading to slowly varying current oscillations. The roles of all these effects are investigated for different electron energies, carrier frequencies, and sizes of the interaction area.