Voltage-Tunable Multifunctional Zoom Imaging Metalenses

Abstract

Many contemporary imaging systems seek tunable focusing components with minimal form factors and versatile functionalities; however, existing solutions are typically limited in size, efficiency, and tuning speed. Here, low-loss all-dielectric metasurfaces integrated with liquid crystals (LCs) are used to demonstrate highly compact multifunctional zoom components. The phase profiles imparted by the metalens are modulated in real time by means of field-dependent LCs, enabling electrically driven continuous focal length variation and active bifocal imaging with low applied voltages (<10 V). These applications are achieved through the systematic design and validation of resonant metasurface elements that ensure the desired metalens response in each LC state. We engineer and fabricate a high-contrast voltage-actuated continuous-zoom LC-metalens with up to 18% total shift in focal length. Additionally, we fabricate simplified large-diameter LC-metalenses, composed of only a few resonator types, that facilitate electrically tunable multidepth imaging. These results demonstrate the promise of electrically controlled LC-embedded zoom-metasurfaces to serve as lightweight and ultrathin multifunctional focusing components, with prospective uses in next-generation imaging devices.