近日，国防科技大学的江天&胡瑜泽及其研究团队取得一项新进展。经过不懈努力，他们研制出面向程控太赫兹开关的颜色编码元器件。相关研究成果已于2024年6月25日在国际知名学术期刊《光：科学与应用》上发表。

该研究团队实验展示了一种光编程太赫兹开关，通过将光学超表面与太赫兹超表面相结合来实现，从而产生2位双通道太赫兹编码。太赫兹超表面由半导体岛和人工微结构组成，通过提供纳秒级超快调制的多个频率通道，实现有效的全光编程。同时，覆盖太赫兹超表面的光学超表面改变了空间光场分布，从而能够获得色码。

根据时域耦合模式理论分析，太赫兹超表面的能量耗散模式可以由颜色激发独立控制，很好地解释了2位编码的原理。本工作为全光程控太赫兹元器件搭建了平台，并可能进一步推进复合超表面在太赫兹操纵中的应用。

据悉，太赫兹调制器在高速无线通信、无损成像等领域发挥着至关重要的作用，引起了广泛的研究兴趣。然而，全光太赫兹调制作为一种超快的动态控制方法，在编码和多功能方面仍然受到限制。

附：英文原文

Title: Color coded metadevices toward programmed terahertz switching

Author: He, Weibao, Cheng, Xiangai, Hu, Siyang, Ren, Ziheng, Yu, Zhongyi, Wan, Shun, Hu, Yuze, Jiang, Tian

Issue&Volume: 2024-06-25

Abstract: Terahertz modulators play a critical role in high-speed wireless communication, non-destructive imaging, and so on, which have attracted a large amount of research interest. Nevertheless, all-optical terahertz modulation, an ultrafast dynamical control approach, remains to be limited in terms of encoding and multifunction. Here we experimentally demonstrated an optical-programmed terahertz switching realized by combining optical metasurfaces with the terahertz metasurface, resulting in 2-bit dual-channel terahertz encoding. The terahertz metasurface, made up of semiconductor islands and artificial microstructures, enables effective all-optical programming by providing multiple frequency channels with ultrafast modulation at the nanosecond level. Meanwhile, optical metasurfaces covered in terahertz metasurface alter the spatial light field distribution to obtain color code. According to the time-domain coupled mode theory analysis, the energy dissipation modes in terahertz metasurface can be independently controlled by color excitation, which explains the principle of 2-bit encoding well. This work establishes a platform for all-optical programmed terahertz metadevices and may further advance the application of composite metasurface in terahertz manipulation.

DOI: 10.1038/s41377-024-01495-1

Source: https://www.nature.com/articles/s41377-024-01495-1