Polarization, the direction in which light vibrates, is invisible to the human eye but provides a great deal of information about the objects with which it interacts. Being able to control and characterize the polarization is important for a range of applications, from biomedical imaging to optical communications. Researchers have developed metasurface optics that can remotely control the polarization of light through space along the path of the beam.
The metasurface optics consists of titanium dioxide nanopillars, arranged in rings on a glass substrate. Each ring of nanopillars, like the ring of a tree, contains information — in this case, polarization information. When light passes through the metasurface, nanopillars encode the polarization information onto the beam. As the beam moves away from the metasurface, it remembers that information and changes polarization, so that at any given point away from the metasurface, the polarization will acquire a specific state.
The metasurface optics were fabricated using a CMOS compatible technology, meaning these compact optical elements could be easily integrated into larger optical systems.