Switching light beams quickly is important in many technological applications. Researchers at ETH have now developed an “electro-opto-mechanical” switch for light beams that is considerably smaller and faster than current models. This is relevant for applications such as self-driving cars and optical quantum technologies.
Self-driving cars have become better and more reliable in recent years. Before they might be allowed to drive completely autonomously on our roads in the near future, however, a few hurdles have to be taken. Above all, the need to assess the surroundings at lightning speed and to recognize people and obstacles takes current technologies to its limits. A team of scientists led by Jürg Leuthold at the Institute for Electromagnetic Fields at ETH Zurich, together with colleagues at the National Institute of Standards and Technology (NIST) in the USA and at Chalmers University in Gothenburg (Sweden), has now developed a novel electro-opto-mechanical switch that might be able to elegantly solve both problems in the future.
Plasmonics as a magic ingredient
To achieve this, the researchers used a magic ingredient known as “plasmonics”. In this technology, light waves are squeezed into structures that are much smaller than the wavelength of the light – which, according to the laws of optics, should be impossible to do. It can be made possible, however, by guiding the light along the boundary between a metal and a dielectric – a substance, such as air or glass, that hardly conducts electric current.
The electromagnetic waves of the light partially penetrate the metal and cause the electrons inside it to oscillate, which results in a hybrid creature made of a light wave and an electronic excitation – the plasmon. More than ten years ago, some well-known physicists already predicted that optical switches based on plasmons could lead to a revolution in data transmission and data processing, as both can be done much faster with photons than with traditional electronics.
Source: “A super-fast “light switch” for future cars and computers”, Zurich ETH News