Turn nanolight on and off

A research team led by Columbia University has developed a unique platform to program a crystal layer and thus produce imaging capabilities that are beyond general limits for demand.

The discovery is an important step towards controlling nanolight, it is light that has access to the smallest length scales imaginable. The work also provides insights for the processing of quantum optical information processing, which aims to solve difficult problems in computer and communication.

“We were able to use ultra-fast nano-scale microscopy to discover a new way to control our crystals with light, thus arbitrarily turning on and off evasive photonic properties,” said Aaron Sternbach, a postdoctoral researcher at Columbia, who is lead researcher on the study is. “The consequences are short-lived, lasting only trillions of one second, yet we are now able to observe these phenomena clearly.”

The research appears in the journal on February 4 Science.

Nature places a limit on how strictly light can be focused. Even in microscopes, two different objects closer to this limit appear to be one. But within a special class of crystalline layers – known as van de Waals crystals – these rules can sometimes be broken. In these special cases, this material can be restrained without any restriction, making it possible to see even the smallest objects clearly.

In their experiments, the Columbia researchers studied the van der Waals crystal called tungsten dieselene, which is of great importance for its possible integration into electronic and photonic technologies, because of its unique structure and strong interaction with light.

When the scientists illuminated the crystal with a pulse, they were able to change the electronic structure of the crystal. The new structure, created by the optical switch, allowed something very unusual to take place: superfine details on the nanoscale can be transported through the crystal and imaged on its surface.

The report shows a new method of controlling the flow of light from nanolight. Optical manipulation on the nanoscale, or nanophotonics, has become a critical interest as researchers look for ways to meet the growing demand for technologies that go far beyond what is possible with conventional photonics and electronics.

Dmitry Basov, professor of physics at Higgins at Columbia University and senior author of the article, believes the team’s findings will spark new research areas on quantum issues.

“With laser pulses, we were able to create a new electronic state in this prototypical semiconductor, even if only for a few seconds,” he said. “This discovery puts us on the path to optically programmable quantum phases in new materials.”