Ultrafast X-ray pulses could reveal atoms in motion

Researchers from the University of Michigan have demonstrated an ultrafast switch for X-rays that will enable scientists to obtain information about the dynamics of molecular motion.

Researchers from the University of Michigan Department of Physics and its new Centre for Optical Coherent and Ultrafast Science (FOCUS) have demonstrated an ultrafast switch for X-rays.

The switch will enable the researchers to follow the movement of constituent atoms, and obtain information about the dynamics of molecular motion.

The U-M researchers used an ultrafast laser source, which acts as a hammer on the surface of a crystal, generating an acoustic pulse that is very short in both time and space.

The pulse modifies the diffraction patterns through the crystal and it can be used to switch energy from one diffracted beam to another making it an ultrafast shutter for X-rays achieving speeds of picoseconds.

‘If we can shutter X-rays very quickly, we have the potential to generate an ultrafast X-ray pulse that can be used to study the dynamics of very complex systems – essentially anything, like proteins, that can be made into a crystal,’ said U-M researcher Matthew F. DeCamp. He added that the ultrafast pulses also could be used to study shock waves as they propagate through materials.

Ferenc Krausz and Christian Spielmann of the Vienna University of Technology, said that the work, ‘opens an entirely new chapter in controlling the time structure of hard X-rays.’

They added, ‘the X-ray switch is a versatile tool that could be added to nearly every beam line without having to touch the source.

‘Such ultrafast switches could become a key component in the X-ray toolbox for probing the structural dynamics of matter.’