Shanghai team in diffusion breakthrough
A team from Shanghai Jiao Tong University said on Thursday that it had developed a way to make materials that can localize light waves and prevent diffusion during transmission.
Researchers said it can ensure quality of information such as images in transmission as no loss happens in the process.
The findings have been published in international science journal “Nature.”
Ye Fangwei, a professor at the university’s School of Physics and Astronomy and leader of the team, explained: “When I speak, everyone hears me, because the wave of the sound diffuses; when you throw a stone into a still lake, the ripple expands, because the wave of the water diffuses; when a laser is propagating in space, the laser spot becomes larger and larger with distance, because the wave of the light diffuses or diffracts. In fact, every type of wave diffuses, and diffusion is a common nature for all waves. That is why the fact that kills the diffusion and localizes waves is a fundamental, long-standing problem in science.
They used moiré lattices, which consist of two superimposed identical periodic structures with a relative rotation angle and are widely seen in life, such as the light and dark stripes seen when two combs are put together with a relative rotation angle.
The light and dark stripes seen when two combs are put together with a relative rotation angle are moiré lattices.
The team found that when it imprinted two moiré lattices in the same crystal material with some rotation angles, they can make light travel in one direction without diffusion.
It means that we might be able to transmit images or information using the moiré-lattice materials, which, in sharp contrast to the existing ones, does not need special designs.
“Our findings provide a new way to localize waves, not only light waves, but also other waves like matter waves,” Ye said.
He said the new findings had a potential application in information transportation, image processing and light manipulations, and inspire other research in several areas of science, including optics, acoustics, condensed matter and atomic physics.
The light does not diffuse when the material is imprinted with two moiré lattices with a rotation angle (right), but diffuses when the lattices are imprinted with another angle.
