A new method for analyzing and controlling the polarization of light has been developed by the Vienna University of Technology (TU Vienna) and Würzburg University researchers. Scientists have utilized thin layers of semiconductor materials for this.
This innovation can aid in the development of advanced computer technology. It also represents a major breakthrough, which influences future study on light and polarization.
The magnetic field in the thin layer rotates the light waves
Faraday Effect is a phenomenon, which states that changes occur in the polarization of light when it travels via a material present in a high magnetic field. But, Andrei Pimenov, a professor at TU Vienna, says that till now the Faraday Effect has been found only in materials in which it was weak. Pimenov, along with his assistant, has conducted experiments on this at the TU Vienna’s Institute for Solid State Physics. Faraday Effect with stronger magnitude can be achieved by the Vienna and Würzburg university researchers with the use of very clean semiconductors and light waves of correct wavelength.
The rotation of light waves into arbitrary directions can be carried out and the polarization path can be controlled by a peripheral magnetic field. Scientists have found that the above effect can be achieved by an ultra thin layer of semiconductor material. Further, if the light waves are transmitted through a polarization filter, researchers can determine whether the light beam will pass or not by rotating its direction. This effect is caused due the behavior of electrons present in the semiconductor.
Researchers used a thin layer of semiconductor mercury telluride in the experiment at TU Vienna and it was exposed to infrared spectral range of light radiation. The terahertz frequency of light is ideal for operation of next generation computers. An external signal controls the electric current in a transistor. Similarly, an external magnetic field controls the light waves in the new research. Hence, the experimental system can be referred as light-transistor, says Pimenov.
This recent experiment on polarization of light could be considered as a version of an optical transistor. The new surprising effect found from the experiment can act as a functional tool for future optical research.