A material that captures and directs light – photonic crystals.Image Credit: J. Joannopoulous/SCIENCE PHOTO LIBRARY
A micron-sized device that produces very intense light by emitting a beam of electrons on a crystal plate. Such devices can be used to make miniature X-ray machines and particle accelerators. Compared to current particle accelerators, the manufacturing process for this chip-like device is shorter, cheaper and more compact. The results of the research were recently published in Nature.
The device was manufactured by researchers at the University of Hong Kong and the Massachusetts Institute of Technology in the United States. It consists of a special piece of silicon called a photonic crystal, an improved scanning electron microscope, and a device to detect emitted light. It uses the electromagnetic field surrounding the electron as it moves, so that the charged particles in the photonic crystal material can be excited and emit light.
The researchers learned from mathematical models that the interaction between crystals and electrons can be enhanced by adding patterns to the crystals. To do this, they etched a grid of circular indentations on the crystals, each about 100 nanometers wide. Light and electrons usually don’t interact much, but by designing the energy and kinetic energy of light to match the energy and kinetic energy of electrons, an unusually large interaction between the two can be created. Yang Yi of the University of Hong Kong said this matching method could eventually increase the intensity of light emission by a factor of 1 million.
Peter Hommelhoff of the University of Erlangen-Nuremberg in Germany said it was worth noting that the device could be used to make miniature particle accelerators. Instead of hitting particles with microwaves, as is often the case, researchers can use intense pulses of light to accelerate particles.
Thomas Krauss of the University of York in the United Kingdom said the new device is a big step towards making not only miniature particle accelerators, but also smaller X-ray machines. X-rays are essentially light waves that are difficult to see with the naked eye because the wavelength is too short. By adjusting the shape of the silicon pattern and the speed of electrons in the device, it is possible to change the wavelength of the emitted light to X-rays.
“When you get an X-ray at the doctor’s, you’re facing a huge machine. Now we can imagine that this can be done with a very small light source on the chip. Krauss said. This could make X-ray technology easier to apply to small or telemedicine facilities, or make it more accessible to first responders at the scene of an accident. (Source: Li Muzi, China Science News)
Related paper information:http://doi.org/10.1038/s41586-022-05387-5