Controlling light has potential for optical effects

Researchers from North Carolina State University (NC State) have developed a method to control light using electric fields. Based around a property of single-layer semiconducting metal compounds, the technique is able to change the direction, intensity and focus of a light beam.

Linyou Cao, co-author of a paper on the research in the American Chemical Society journal Nano Letters, explained that the technique is similar to that used to write information into computer memory. “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,” he said. “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."

Photons — the basic unit of light — do not carry any electric charge, and therefore cannot be influenced directly by electric fields. Instead, the technique works by changing the optical properties of materials that interact with photons. The team used atomic monolayers of semiconducting compounds known as transition metal dichalcogenides; specifically, molybdenum sulphide, tungsten sulphide and tungsten selenide.