Single attosecond pulse generation from a capacitor target irraidated by a circularly polarized laser

Brilliant single-attosecond pulses are highly desired due to their exceptional capability for real-time observation and control of electron dynamics at the atomic scale. In this study, we propose a method for generating intense single attosecond pulses through the interaction between a circularly polarized (CP) laser and a capacitor target. Simulations demonstrate that once the capacitor is fully charged, the stored electrostatic energy can facilitate the formation of the isolated electron bunch while significantly boosting its longitudinal momentum. Consequently, coherent synchrotron emission, known as the most efficient high-order harmonic generation mechanism, is successfully triggered for just one time. As a result, a single attosecond pulse with energy enhanced by at least one order of magnitude compared to single nanofoil cases is produced after a filter. Compared with the linearly polarized case, our scheme not only enables the robust generation of a single attosecond pulse without the need for meticulous selection of the filtering range but also produces attosecond pulses that are elliptically or even nearly circularly polarized. Furthermore, these pulses may carry orbital angular momentum due to the conservation of angular momentum. Such versatile pulses have the potential to advance the research on the magnetism and chirality of matter with high spatial and temporal resolution.