With advancements in optical sciences and applications, there is a growing demand for multifunctional optical devices capable of integrating as many wave-control functionalities as possible into a single, ultra-compact system.
However, optical devices made from conventional dielectrics rely on the propagation phases of light, which inherently results in bulky device sizes (relative to wavelengths) and/or low efficiencies (due to the absence of magnetic responses). Furthermore, the lack of additional degrees of freedom to manipulate light makes it challenging to use conventional dielectrics to create compact optical devices with multiple functionalities—an issue that significantly hinders optical integration.
Metasurfaces, ultra-thin metamaterials composed of planar subwavelength microstructures with tailored optical responses arranged in specific, pre-designed sequences, offer extraordinary capabilities for controlling light waves and have garnered significant attention in recent years. By designing both the metaatoms and their arrangement, scientists have developed various metasurfaces that locally control scattered waves in terms of phase and polarization, enabling the formation of tailored light beams in the far field based on Huygens’ principle. This approach has led to the realization of numerous wave-manipulation functionalities, including bi- and multifunctional capabilities within a single meta-device.
To read more, click here.