23–28 Aug 2026
America/Los_Angeles timezone

Self-seeded x-ray mixer for attosecond pulse metrology

WEP33
26 Aug 2026, 17:00
1h
Poster Presentation Session 12: Advanced FEL Modes Wednesday Poster Session

Speaker

Federico Vismarra (SLAC National Accelerator Laboratory)

Description

Attosecond pump-probe experiments are a long-sought tool to observe electronic processes on their natural timescales; however, slippage during FEL amplification complicates the ability to set short delays. At LCLS, we have recently demonstrated pump-probe measurements with sub-fs delays by using harmonic pulse pairs (w/2w). A soft x-ray delay line will enable general two-color operation, but challenges remain to quickly identify time-zero and estimate pulse lengths.

Here, we present an attosecond soft x-ray cross-correlator. We consider a self-seeding type geometry in which lasing from two colors (w1, w2) is synchronized using an x-ray delay line such that the microbunching develops heterodyne components (w1 + w2). Measuring the beat frequency provides a nearly background-free measure of the cross-correlation signal. Because the mixing is done via bunching, the cross-correlation signal is not a simple measure of the x-ray overlap, but depends also on the dynamic structure of microbunching.

Funding Agency

This work was supported by the Basic Energy Sciences Accelerator and Detector Research program under Contract No. DE-AC02-76SF00515, and the Office of Basic Energy Science Accelerator and Detector Res

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Authors

David Cesar (SLAC National Accelerator Laboratory) Federico Vismarra (SLAC National Accelerator Laboratory)

Co-authors

Agostino Marinelli (SLAC National Accelerator Laboratory) Sean OTool (Stanford University)

Presentation materials

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