太赫兹超导约瑟夫森等离激元器件的研究

The lack of high performance terahertz (THz) devices is still a bottleneck for the development and application of THz technology. The THz devices based on surface plasmons in conductor and superconductor structures have shown good prospects in application. The resonance frequency of Josephson plasmon in the layered superconductor is in the THz frequency range. Josephson plasmon is arisen from the collective oscillations of the superconducting electron pairs tunnelling between superconducting layers, and has many unique properties such as strong nonlinear effect. In this application, we plan to use layered high temperature superconductor develop THz Josephson plasmon devices with the design method of plasmonic devices and metamaterials. We use the periodic subwavelength structures to excite surface Josephson plasmons, study the temperature and current tuning properties of Josephson plasmon devices, and explore the new type of THz detectors. We plan to build THz pump-probe spectroscopy system and study the nonlinear effects of devices under the excitation of intense THz radiation. This study is not only of great significance for the scientific research such as high temperature superconductor physics, but also greatly beneficial to develop new type of THz devices with high performance.

高性能太赫兹器件的缺乏依然是限制太赫兹技术发展和应用的瓶颈。基于导体和超导结构中表面等离激元的太赫兹器件已经展现了良好的应用前景。层状结构超导体中的约瑟夫森等离激元的谐振频率在太赫兹频段，它来源于层间隧穿的超导电子对的集体振荡，并具有很强的非线性效应等特性。本申请中，我们拟采用层状结构高温超导材料，借鉴等离激元器件和超材料的设计方法，开发基于约瑟夫森等离激元的太赫兹器件。利用周期性亚波长结构实现表面约瑟夫森等离激元的激发，研究约瑟夫森等离激元器件的温度和电流调控特性，并探索用于太赫兹探测的新型器件。搭建太赫兹泵浦-探测光谱系统，研究器件在强场太赫兹激励下的非线性效应。这项研究不仅对于高温超导物理等科学研究具有重要的意义，也将大大推动新型高性能太赫兹器件的开发。

本报告对国家自然科学基金青年项目《太赫兹超导约瑟夫森等离激元器件的研究》（项目编号61701219）课题进展进行总结。本项目基于超导薄膜和超导器件的约瑟夫森效应，开发基于约瑟夫森等离激元的新型超导太赫兹器件。代表性研究成果包括开发出基于超导超材料的高速太赫兹调制器，阐明了器件工作机制；开发出基于超导薄膜的高Q值超材料，观测到了约瑟夫森等离激元的激发；基于液晶、二氧化钒等可调谐材料，开发出可调谐和可编程的太赫兹超材料，实现了太赫兹波的动态调控。这一工作对于研究超导器件的工作机理和太赫兹技术的应用具有一定的意义。