Researchers from North Carolina State University have discovered a technique for controlling light with electric fields. Lin-you Cao, an assistant professor of materials science and engineering at NC State, and his collaborators have developed a technique that allows them to change the refractive index for visible light in some materials. They worked with a class of atomically thin semiconductor materials called transition metal dichalcogenide monolayers.
Their method is similar to the technique used to provide the computing capabilities of computers. In computers, an electric field is used to turn electric current on or off, which corresponds to logic 1 and logic 0, the basis of binary code. With this new discovery, a light may be controlled to be strong or weak, spread or focused, pointing one direction or others by an electric field. Using this technique, they achieved significant, ‘tunable’ changes in the index within the red range of the visible spectrum.”
Currently, the new technique allows researchers to tune the refractive index by any amount up to 60 percent– two orders of magnitude better than previous results. The greater the voltage applied to the material, the greater the degree of change in the index. And, because the researchers are using the same techniques found in existing computational transistor technologies, these changes are dynamic and can be made billions of times per second.
Professor Cao says this is only a first step and thinks they can optimize the technique to achieve even larger changes in the refractive index. They also plan to explore whether this could work at other wavelengths in the visual spectrum. Just as computers have changed our way of thinking, this new technique will likely change our way of watching. For instance, it could shape light into arbitrary patterns, which may find applications in goggle-free virtual reality lenses and projectors, the animation movie industry or camouflage.
Source: North Carolina State University (NCSU)
"Giant Gating Tunability of Optical Refractive Index in Transition Metal Dichalcogenide Monolayers" - Yiling Yu et al. - Nano Letters - May 15, 2017 - DOI: 10.1021/acs.nanolett.7b00768
Source Reference: https://watchers.news/2017/05/26/researchers-discovered-a-technique-for-controlling-light-with-electric-fields/
Credit for Featured image at top of page: NCSU