Researchers at Chalmers University of Technology have built a very simple nanoantenna that directs red and blue colours in opposite directions, even though the antenna is smaller than the wavelength of light. The findings - published in the online journal Nature Communications can lead to optical nanosensors being able to detect very low concentrations of gases or biomolecules. A structure that is smaller than the wavelength of visible light (390-770 nanometers) should not really be able to scatter light. But that is exactly what the new nanoantenna does. The trick employed by the Chalmers researchers is to build an antenna with an asymmetric material composition, creating optical phase shifts
