An artist's impression of an optically excited gas of electronic carriers confined to the planes of the layered van der Waals semiconductor tungsten diselenide. The consequent hyperbolic response permits passage of nanolight. Image: Ella Maru Studio.A team led by researchers at Columbia University has developed a unique platform for programming a layered crystal, allowing them to produce imaging capabilities beyond common limits on demand.
This discovery is an important step towards the control of nanolight, which is light that can access the smallest length scales imaginable. The work also provides insights for the field of optical quantum information processing, which aims to solve difficult problems in computing and communications.
"We were able to use ultrafast nano-scale microscopy to discover a new way to control our crystals with light, turning elusive photonic properties on and off at will," said Aaron Sternbach, a postdoctoral researcher at Columbia University and lead investigator on the study. "The effects are short-lived, only lasting for trillionths of one second, yet we are now able to observe these phenomena clearly." The researchers report their findings in a paper in Science.
Nature sets a limit on how tightly light can be focused. Even in microscopes, two different objects that are closer together than this limit would appear to be one. But within a special class of layered crystalline materials known as van der Waals crystals these rules can, sometimes, be broken. In special cases, light can be confined without any limit in these materials, making it possible to see even the smallest objects clearly.
In their experiments, the Columbia researchers studied a van der Waals crystal called tungsten diselenide. This crystal is of great interest for integration into electronic and photonic technologies because of its unique structure and strong interactions with light.
When the scientists illuminated the crystal with a pulse of light, they were able to change its electronic structure. This new structure, created by the optical-switching event, allowed something very uncommon to occur: super-fine details, on the nanoscale, could now be transported through the crystal and imaged on its surface.
The paper thus reports a new method for controlling the flow of nanolight. Optical manipulation on the nanoscale, or nanophotonics, has become a critical area of interest as researchers seek ways to meet the increasing demand for technologies that go well beyond what is possible with conventional photonics and electronics.
Dmitri Basov, professor of physics at Columbia University and senior author of the paper, believes the team's findings will spark new areas of research in quantum matter. "Laser pulses allowed us to create a new electronic state in this prototypical semiconductor, if only for a few pico-seconds," he said. "This discovery puts us on track toward optically programmable quantum phases in new materials. "
This story is adapted from material from Columbia University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.