Crystal device could be used to build tiny particle accelerators

Karmela Padavic- Callaghan is a writer.

A micrometre-sized device that produces light by firing a beam of electrons over a slab of crystal could be used to build small machines. The chip-sized devices could be made more quickly and cheaply.

Yi Yang and his colleagues at the University of Hong Kong and the Massachusetts Institute of Technology built a device that consists of a special piece of Silicon, a modified electron microscope and a device that can detect light. The set-up takes advantage of the electromagnetic fields that surround electrons as they move, which makes charged particles within a nearby material.

From mathematical models, the researchers knew that they could enhance the interactions between the crystal and the electrons by adding a pattern to them. Light and electrons don't interact a lot, but engineering the energy and momentum of the light to match that of the electrons allows for large interactions. Light emissions could be enhanced up to a million times.

The light can be used to help scientists learn about the internal structure of materials and to communicate.

Peter Hommelhoff at the University of Erlangen-Nuremberg in Germany says that it can be used to make small particles. It's more common for researchers to use intense light to accelerate particles than it is to hit them with microwaves.

According to Thomas Krauss at the University of York in the UK, the new device may be a step toward smaller X-rays. Light waves are too short to see in x-rays. It could be possible to change the wavelength of emitted light to X-rays by changing the pattern of electrons in the device.

An X-ray at the doctor is a big deal. He says that it's possible to do it with a light source on a chip. It could make X-ray technology more accessible for small medical facilities or first responders in an accident.

The journal is titled Nature.