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arXiv · 2508.19020

Spatiotemporal shaping of attosecond X-rays with time-dependent orbital angular momentum

Chenzhi Xu·Jiawei Yan·Gianluca Geloni·Christoph Lechner·Haixiao Deng
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Abstract

Attosecond X-ray pulses are indispensable for exploring ultrafast phenomena in matter on Angstrom and attosecond scales. Here we propose a new method to realize spatiotemporal shaping of attosecond X-rays through temporal control of the orbital angular momentum mode content using an X-ray free-electron laser. The method exploits transverse-mode-dependent frequency pulling in a deliberately detuned second stage, together with slippage between the seed and the amplified radiation. Three-dimensional simulations show a double-spike waveform in which the two spikes carry different dominant topological charges. The spike separation is tunable and can reach several hundred attoseconds. This provides a source-level route to spatiotemporally structured attosecond X-rays with controllable temporal structure and topological mode content.

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Chenzhi Xu, Jiawei Yan, Gianluca Geloni, Christoph Lechner, Haixiao Deng. 2026-01-12. Spatiotemporal shaping of attosecond X-rays with time-dependent orbital angular momentum. https://arxiv.org/abs/2508.19020

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