Metasurfaces composed of designed nanoscale, subwavelength optical elements ("meta-atoms") arranged in a plane have been established as a versatile and efficient platform for controlling the properties of light fields, including their wavefront, polarization, and spectral properties. However, most metasurfaces realized so far were passive and linear and already during fabrication, their optical response was permanently encoded into the structure.
Metasurfaces are two-dimensional arrangements of designed nanoscale building blocks that offer exquisite control over the properties of light fields and allow for the realization of ultra-compact, highly functional photonic devices. Within META-ACTIVE, the spatial light control provided by optical metasurfaces will be combined with the capability of their resonant building blocks to enhance light-matter interactions and/or facilitate a tunable optical response. Pertinent research questions encompass various projects in the areas of light-emitting metasurfaces, programmable metasurfaces and metasurface-enhanced detection.
In the framework of the International Research Training Group (IRTG) 2675 "META-ACTIVE" funded by the German Research Foundation (DFG), we will create and investigate active metasurfaces, which emit, detect and dynamically manipulate light, making use of the capability of their resonant meta-atoms to enhance the interaction of light with nanoscale matter. By combining the nanoantenna effect of the individual meta-atoms with the additional degrees of freedom offered by the arrangement, metasurfaces provide opportunities for tailoring light-matter interactions far exceeding the respective capabilities of individual nanoantennas. This scientific vision will lay the foundations for new types of high-performance (quantum) light sources, programmable optical systems, and enhanced detectors based on the metasurface concept.