Design of a terahertz encoding metalens with adjustable focusing intensity

This paper presents a terahertz coded metalens with adjustable focusing efficiency. By integrating the phase change material GST-225 with the plasma metasurface and employing the transmission phase principle for phase modulation, flexible control of the single-focus focusing efficiency is achieved. Additionally, a dual-focus focusing metalens is devised. Leveraging the far-field scattering principle of the coded metasurface, the focal angle of the metalens can be adjusted, and it can be expanded to a dual-focus system through complex coding addition. In this system, by adjusting the crystallinity corresponding to different codes, the system can show different focusing efficiencies at each focus. The proposed dual-focus in this paper enables separate adjustment of focusing efficiency, offering a promising solution for on-chip and tunable devices in terahertz imaging and communication systems. (c) 2024 Optica Publishing Group. All rights, including for text and data mining (TDM), Artificial Intelligence (AI) training, and similar technologies, are reserved.