基于新型钙钛矿材料的光场调控太赫兹超表面仿真研究

Simulation of terahertz metasurface controlled by light fieldbased on novel perovskite materials

为实现高效太赫兹调控,迫切需要一种高效且成本低的材料。新型钙钛矿材料由于其优异的光电特性,加上钙钛矿制备工艺简单、可大批量生产等优点,非常适合作为太赫兹超材料的活性材料,通过外部激励改变活性材料的属性,可灵活调控太赫兹波。因此,选择新型钙钛矿材料外加光场调控太赫兹,分析在光场作用前(绝缘态)和在光场作用后(金属态)两种状态对单元结构太赫兹宽波段下幅值和相位的影响。设计出光场灵活调控的钙钛矿基1 bit太赫兹编码超表面结构,该结构由有机无机杂化钙钛CH_(3)NH_(3)PbI_(3)(MAPbI_(3))、聚酰亚胺和铝构成。通过CST仿真结果显示,该超表面结构在光场的调控下能够实现宽谱(0.1、1、2、6 THz)太赫兹波的180°相位差变化,经过超表面编码结构的设计,同一编码序列实现远场波束的变换。研究结果表明,基于光场操控钙钛矿材料的编码超表面为实现灵活的太赫兹波调控提供了新的思路,在太赫兹通信、安检、生物医学成像等方面具有巨大的应用潜力。

In recent years,the terahertz control technology has shown a good application prospect in the fieldsof detection,imaging,wireless network communication and so on,and has attracted the attention of scholars at homeand abroad.To achieve efficient terahertz regulation,an efficient and low-cost material is urgently needed.Newperovskite materials have become one of the most promising candidates for high stability optoelectronic devices due totheir excellent photoelectric properties.At the same time,perovskite has the advantages of simple preparation processand mass production,thus it is very suitable to be used as the active material of terahertz metamaterials.The propertiesof active materials can be changed by external excitation,and terahertz waves can be adjusted flexibly.Therefore,thispaper selects a new perovskite material with external optical field to regulate terahertz waves,and analyzes theinfluence of two states-before the optical field action(insulating state)and after the optical field action(metallic state)on the amplitude and phase of the unit structure in the wide band of terahertz.A perovskite-based 1bit terahertz codingmetasurface structure with flexible light field regulation was designed.The structure is composed of organic andinorganic hybrid perovskite CH_(3)NH_(3)PbI_(3)(MAPbI_(3)),polyimide and aluminum.The simulation results of CST showthat the metasurface structure can realize 180°phase difference change of wide spectrum(0.1,1,2,6 THz)terahertzwaves under the control of light field.After the design of metasurface coding structure,the same coding sequence can realize the transformation of far-field beam.The results show that the encoding metasurface based on optical fieldmanipulation of perovskite materials provides a new idea for realizing flexible terahertz wave regulation,and has greatapplication potential in terahertz communication,security check,biomedical imaging and so on.