Journal Article

Sub-femtosecond precision measurement of relative X-ray arrival time for free-electron lasers

Schorb, S., Bostedt, C., Helml, W., Bionta, M. R., Galler, A., Hartmann, N., Kane, D. J., Feurer, T., L. Molodtsov, S., Ferguson, K. R., Carron, S., Coffee, R. N., Grünert, J., Glownia, J. M., White, W. E., Bozek, J., Hauri, C. P., Castagna, J.-C., Swiggers, M. L., Fry, A. R.

2014

Overview

Some X-ray free-electron laser facilities are pushing towards sub-10 fs pulses, making it desirable to reduce errors in X-ray/optical delay measurements to the 1 fs level. Researchers have now demonstrated X-ray measurements with a temporal resolution shorter than 1 fs, opening up new possibilities for time-resolved X-ray experiments. Today's brightest coherent X-ray sources, X-ray free-electron lasers, produce ultrafast X-ray pulses for which full-width at half-maximum durations as short as 3 fs have been measured 1 . There has been a marked increase in the popularity of such short pulses now that optical timing techniques have begun to report an X-ray/optical delay below ∼10 fs r.m.s. errors. As a result, sub-10 fs optical pulses have been implemented at the Linac Coherent Light Source (LCLS) X-ray beamlines, thus warranting a push to reduce the error in X-ray/optical delay measurements to the 1 fs level. Here, we report a unique two-dimensional spectrogram measurement of the relative X-ray/optical delay. This easily scalable relative delay measurement already surpasses previous techniques by an order of magnitude with its sub-1 fs temporal resolution and opens up the prospect of time-resolved X-ray measurements to the attosecond community.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 639/624/400/1106 / 639/766/400/584 / Applied and Technical Physics / Delay / Electrons / Errors / Free electron lasers / Lasers / letter / Light sources / Optical pulses / Particle physics / Photonics / Physics / Quantum Physics / Short pulses / Silicon nitride / Temporal resolution / X-rays