Scientists and engineers working in the fields of optical and photonics have been captivated by the rapidly developing, interdisciplinary field of metasurfaces. They view these advanced materials as a path to a new breed of ultra-compact flat optics, such as camera lenses. But most of the metasurfaces that have been demonstrated up to this point have been predesigned for a single purpose; only lately have researchers started to look into the potential of “active” metasurfaces that can be reconfigured instantly.
A study team recently demonstrated one such active metasurface. It is a hybrid of silicon and so-called phase-change materials, allowing for rapid changes in transparency and optical properties. According to the experts, the material may open up new possibilities in LiDAR, ultrathin photographic lenses, tunable lenses, and other application areas.
Metasurfaces are engineered materials that function as light scatterers or resonators and are decorated with bands of nanoscale, subwavelength structures on ultrathin substrates. When constructed properly, these arrays can regionally alter a propagating light field’s amplitude, phase, and polarization. As a result, the technology behind metasurfaces promises to replace large optical components with extremely tiny elements, opening the door for the development of the next generation of flat lenses and other small-form-factor optics.
Metasurfaces are typically made and designed as passive objects, with the modifications they make to the light field frozen during fabrication.