Rapid Polarization-Controlled Depth Sensing and Imaging with an Electrically Tunable Metalens
Yeseul Kim, J.‐L. Lee, Wei-Hong Yeo, Xiaotong Li, Wonsik Kim, Young‐Ki Kim, Trevon Badloe, Cheng Sun, Hao F. Zhang, Junsuk Rho
Abstract
We demonstrate an electrically tunable metalens that combines hydrogenated amorphous silicon (a-Si:H) meta-atoms with a liquid crystal (LC) layer for rapid polarization-controlled depth sensing and imaging. Two independent focusing profiles for left-circularly polarized (LCP) light and right-circularly polarized (RCP) light are encoded via propagation and geometric phases in a single metasurface. Adjusting the LC voltage and the incident polarization among the LCP, RCP, and their superposition enables millisecond-scale reconfiguration. Under pure circular polarization, the metalens yields a single high-fidelity focal spot or an image. Linearly polarized light produces two rotating images, whose relative orientation encodes object depth. Experiments match theory and confirm a full π rotation of the image during focal scanning. The device offers a compact, real-time platform for imaging and depth sensing in microscopy, holography, and adaptive optics.