Ultrahigh-amplitude isolated attosecond pulses generated by a two-color laser pulse interacting with a microstructured target.

ABSTRACT

A unique electron nanobunching mechanism using a two-color laser pulse interacting with a microstructured foil is proposed for directly generating ultraintense isolated attosecond pulses in the transmission direction without requiring extra filters and gating techniques. The unique nanobunching mechanism ensures that only one electron sheet contributes to the transmitted radiation. Accordingly, the generated attosecond pulses are unipolar and have durations at the full width at half-maximum about 5 attoseconds. The emitted ultrahigh-amplitude isolated attosecond pulses have intensities of up to ∼10^{21}W/cm^{2}, which are beyond the limitations of weak attosecond pulses generated by gas harmonics sources and may open a new regime of nonlinear attosecond studies. Unipolar pulses can be useful for probing ultrafast electron dynamics in matter via asymmetric manipulation.