X-rays are already being used in many fields to study the microscopic structure of matter. Now a group of researchers from the University of Michigan Department of Physics have demonstrated an ultrafast switch for X-rays.
The switch will enable the researchers to follow the movement of constituent atoms, and actually obtain information about the dynamics of molecular motion.
The 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. That pulse modifies the diffraction patterns through the crystal, and it can be used to switch energy from one diffracted beam to another.
In other words, it becomes an ultrafast shutter for X-rays, enabling them to capture motion within molecules just as a stop-action camera enables light to capture motion during a football game. But where sports photographers might be working with average shutter speeds of about a 500th of a second, the physicists were achieving speeds of picoseconds (one trillionth of a second).
"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," says DeCamp, one of the researchers. He notes that the ultrafast pulses also could be used to study shock waves as they propagate through materials.
