Perovskite-enabled transmission-reflection switchable terahertz metasurface for independently wavefront manipulation

This paper designs a perovskite-metal hybrid metasurface that can independently control the phase of transmitted and reflected waves under the same incident terahertz wave, thereby achieving different wavefront functions in different electromagnetic spaces. The designed metasurface has two layers of perovskite-metal and one dielectric layer. When the perovskite is in metallic state, the metasurface works in transmission mode; when the perovskite is in insulating state, the metasurface works in reflection mode. By utilizing the geometric phase principle and the convolution principle, a four-focal-lens is realized in the transmission space, while generating a four-channel orbital angular momentum in the reflection space. This work offers potential applications in dynamic imaging, communication, and other fields.