Demonstration of a picosecond Bragg switch for hard X-rays in a synchrotron-based pump–probe experiment

Abstract

A benchmark experiment is reported that demonstrates the shortening of hard X‐ray pulses in a synchrotron‐based optical pump–X‐ray probe measurement. The pulse‐shortening device is a photoacoustic Bragg switch that reduces the temporal resolution of an incident X‐ray pulse to approximately 7.5 ps. The Bragg switch is employed to monitor propagating sound waves in nanometer thin epitaxial films. From the experimental data, the pulse duration, diffraction efficiency and switching contrast of the device can be inferred. A detailed efficiency analysis shows that the switch can deliver up to 109 photons s−1 in high‐repetition‐rate synchrotron experiments.

A new concept for temporal gating of synchrotron X-ray pulses

“…4(e). The intensity of the selected pulse is 2.1 times the intensity of the accumulated background in the same pixel which corresponds to an on-off contrast of $ 550 (Sander et al, 2016(Sander et al, , 2019. If the theoretical diffraction efficiency of 33% were achieved, the on-off contrast would exceed 10 5 .…”

“…With the advent of highpower radiation sources adaptive optics are being developed to enable dynamic optimization of the beam conditions (Stoupin et al, 2010;Quintana et al, 1995;Berman & Hart, 1991;Yashchuk et al, 2015;Goto et al, 2015). Today most parameters of the emitted pulses can be tuned, for example energy and bandwidth, beam divergence, focal size or even the time structure of the emitted pulse itself (Schoenlein et al, 2000;Sander et al, 2019). The remaining parameter that can only be controlled with large effort is the time structure of the emitted pulse train.…”

Full Spatiotemporal Control of Laser-Excited Periodic Surface Deformations

“…The devices are optimized for installation at synchrotron beamlines. A prominent example is the picosecond Bragg switch (Pi-coSwitch), which shortens an incident synchrotron x-ray pulse to a duration of few picoseconds [66]. The coherent control of thTGs similar to case B [c.f.…”

Concepts and use cases for picosecond ultrasonics with x-rays

“…For ultrathin layers, crystals consisting of light atoms, nanoparticles or advanced concepts using resonant diffraction, however, FELs are ideal as they pair high photon flux and sub-picosecond time resolution [37] , [38] , [39] . Synchrotron radiation sources typically lack temporal resolution, which can be improved via fs-pulse slicing schemes [40] , [41] , x-ray streak camera setups [22] , [23] , [42] , special short-pulse filling patterns [43] , [44] or picosecond Bragg switches [45] , [46] , that all come at the cost of a reduction of the photon flux by multiple orders of magnitude.…”