Using strain to control echoes in ultrafast optics

Researchers at MAX IV measured echoes produced by silicon crystals using the coherent X-ray based technique, tele-ptychography, at NanoMAX imaging beamline. Their findings reveal that strain can be used to tune the time delay of echoes, an important step for tailoring ultrafast X-ray optics.

“The use of coherent X-rays to visualize echoes is new. This is the first time it has been used for this purpose, however, the technique itself is not new,” said Dina Carbone, MAX IV Beamline Scientist and project leader.

Echoes are parallel, monochromatic X-ray beams which appear, with time delay, from the diffraction of perfect crystals, which are often used in ultrafast optics systems. Dynamical diffraction effects produce echoes.

Echoes are difficult to observe because of their proximity to each other—only a few microns apart—and appear even closer in the presence of strain, explained Carbone. “We knew it would become possible to see them using this new special approach. It would also be quite a challenge because we had to build an ad-hoc setup at NanoMAX. The experience of the group from PSI [Paul Scherrer Institute] was quite crucial.”

Read more on the MAX IV website

Image: Experimental setup for tele-ptychography at NanoMAX beamline. 

Credit:  Angel Rodriguez-Fernandez