Scientists may have found a way to replicate the fascinating natural phenomena of aurora borealis after a recent discovery of an elegant way of manipulating light using a ‘synthetic’ Lorentz force.
Theoretical physicists from the University of Exeter have created a new technique to create tuneable artificial magnetic fields, which enable photons to mimic the dynamics of charged particles in real magnetic fields. This phenomenon is responsible for the magical aurora seen in every aspiring traveller consumed by wanderlust.
The recent research published in Nature Photonics journal could influence future photonic devices as it provides a new way of manipulating light below the diffraction limit. When charged particles, like electrons, pass through a magnetic field they feel a Lorentz force due to their electric charge, which curves their trajectory around the magnetic field lines.
The Lorentz force plays an essential role in the beautiful Northern Lights to the famous quantum-Hall effect. Klaus von Klitzing received the Nobel Prize in Physics in 1985 for discovering the quantum Hall effect, five years after the observation was made at the Grenoble High Magnetic Field Laboratory. Since its discovery 40 years ago, the quantum Hall effect has inspired new theories and led to experimental discoveries in a range of fields beyond solid-state electronics to photonics and quantum entanglement.
According to phys.org, the research team from Exeter have shown that it is possible to create artificial magnetic fields for light by distorting honeycomb metasurfaces and ultra-thin 2-D surfaces that are engineered to have structure on a scale much smaller than the wavelength of light.
Speaking to phys.org, Charlie-Ray Mann, the lead scientist and author of the study, explains, “These metasurfaces support hybrid light-matter excitations called polaritons, which are trapped on the metasurface. They are then deflected by the distortions in the metasurface in a similar way to how magnetic fields deflect charged particles. By exploiting the hybrid nature of the polaritons, we show that you can tune the artificial magnetic field by modifying the real electromagnetic environment surrounding the metasurface.”