Bright isolated light pulses reaching 18 attoseconds from high-order harmonic generation by post-compressed Yb lasers.

Gao, Jingsong; Hasan, Mahmudul; Liang, Hao; Guo, Ziyang; Zhang, Chi; Tsai, Ming-Shian; Yuan, Yiming; Eisenhutt, Zach et al. · Nat Commun · 2026

basic_science · Level V

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Abstract

Generating ever-shorter and brighter light pulses is a central goal of ultrafast science, enabling coherent control and observation of electron dynamics on their natural timescale. State-of-the-art isolated attosecond pulse generation currently achieves pulse durations of 40-50 attoseconds. Here we demonstrate isolated attosecond light pulses with durations of 18 attoseconds, via high-order harmonic generation driven by a post-compressed industrial-grade Yb laser system. The high-harmonic spectrum spans photon energies from 50 to 320 eV, covering the carbon K-edge, with a calibrated photon flux exceeding 10<sup>12</sup> photons per second. Pulse durations were characterized by angle-resolved photoelectron streaking in helium and optimized using a series of filters with different thicknesses to compensate the attochirp. We further developed a robust, fast-converging pulse-retrieval algorithm capable of reconstructing broadband isolated attosecond pulses and double pulses. These results establish Yb-laser-driven high-order harmonic generation as a powerful platform for bright isolated attosecond sources and next-generation ultrafast spectroscopy.