Extreme shaping of isolated attosecond pulses with double temporal peaks driven by 1030 nm few-cycle Yb-doped lasers

Attosecond pulse shaping has attracted significant interest in both free-electron lasers and high-order harmonic generation (HHG). However, extreme shaping of attosecond pulses—where the temporal profile is split into two distinct peaks accompanied by a spectral π -phase jump—has so far been achieved primarily in attosecond pulse trains, but not in isolated attosecond pulses (IAPs), thereby limiting their temporal resolution. Here, we propose an efficient method for generating extremely shaped IAPs using a few-cycle, 1030 nm Yb-doped laser and argon gas. In this approach, an extended HHG spectrum containing the Cooper minimum is produced in argon, while appropriate wavefront rotation of the driving laser is induced by the combination of high-intensity few-cycle lasers and high gas pressure. As a result, the earliest and strongest attosecond pulse with a split temporal profile can be spatially isolated in the far field using a circular spatial filter. Phase-matching analysis reveals that the strongest harmonic emission bursts in the gas medium arise from a non-adiabatic phase-matching mechanism. The proposed scheme has been validated under varying gas pressure, laser intensity, carrier-envelope phase, pulse duration, and laser chirp, consistently demonstrating robust performance. This confirms its experimental feasibility without the need for perfect few-cycle laser conditions. This work offers a novel route for generating shaped attosecond light sources, enabling new possibilities for controlling and probing electron dynamics in various systems.