基于微流控系统的太赫兹频段数字超材料

Recently, reconfigurable metamaterials have attracted increasing interests due to their powerful capabilities of manipulating electromagnetic (EM) waves. In order to realize different functionalities based on a single metamaterial device, the reconfiguration at the unit cell level is of importance. In the microwave range, researchers have demonstrated active metamaterial devices with the capability to control the property of an individual unit cell. However, in the terahertz (THz) region, it is still very challenging to achieve unit cell level reconfiguration due to technical difficulties...As one type of reconfigurable metamaterials, digital metamaterials (DMs) have found a wide range of applications since it first was demonstrated in the microwave range. The unit cell of the digital metamaterial (DM) can be tuned to work in different digital states, and a single metamaterial device can manipulate EM waves in different manners. Functionalities such as beam focusing and radar cross-section reduction have been shown using microwave DMs. Based on this concept, a reflective-type 1-bit THz digital metamaterial based on a microfluidic system is proposed in this project. Liquid metals are pumped into and out of the designed microfluidic channels to change the digital state of the unit cell, realizing the reconfiguration at the unit cell level. The design and optimization of unit cell, the fabrication of micro-channels and the control of liquids using micro-pumps will be investigated, followed by the experimental validation of the THz DM. The proposed device is expected to further enhance the capabilities of metamaterials for the control and manipulation of THz waves, and can serve as a versatile platform for realizing different functionalities using a single metamaterial device.

近年来，可重构电磁超材料因其对电磁波强大灵活的操控能力受到了广泛关注。为了在单一器件上实现对电磁波不同方式的调控，超材料在单元层面的可重构显得尤为重要。微波频段现已实现了对超材料单元电磁响应的独立控制，但太赫兹超材料的可重构由于技术手段的限制依旧处于阵列层面，对单元的独立调控方法仍有待探索。.数字超材料作为一种在单元层面可重构的电磁超材料，已经在微波频段展示出波束汇聚、RCS缩减等多种功能。根据这一概念，本项目提出了基于微流控系统的太赫兹频段反射型1比特数字超材料。项目拟结合微流控技术，利用设计的微管道和液态金属构成基本数字单元；通过对微管道内液态金属的精确泵入控制来改变单元的数字状态，实现数字单元的可重构。本项目将重点研究数字单元的设计优化、微管道的制备以及微流体的精确驱动与控制等内容，以期在太赫兹频段实现数字超材料并完成实验验证，从而进一步提升电磁超材料器件对太赫兹波的调控能力。

随着太赫兹技术的发展，对基于电磁超材料的太赫兹器件的可重构化收到了越来越广泛的关注。为了在单一器件上实现电磁波不同方式的调控，超材料在单元层面的可重构显得尤为重要。数字超材料作为一种在单元层面可重构的电磁超材料，已经在微波频段展示出波束汇聚、RCS缩减等多种功能。本项目研究了基于微流控系统的太赫兹频段反射型1比特数字超材料。结合数字微流控技术，利用设计的PDMS微管道泵入液态金属形成基本数字单元；通过对微管道内液态金属的泵入体积及位置进行精确控制，来改变单个Ω型谐振单元的数字状态，实现数字单元的可重构。本项目研究了数字单元的设计优化、微管道的制备与改性，以及微流体的精确驱动与控制等内容，在太赫兹频段实现了反射型1比特数字超材料并完成实验验证。使得同一器件在不同编码方式下对电磁波具有不同的调控方式，有望作为一种低成本、实现方式简单的可调控太赫兹器件在RCS缩减、可调透镜等方向获得应用。