Content of TOPICAL REVIEW—Terahertz physics in our journal

Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For selected: Download citations EndNote Ris BibTeX Toggle thumbnails Select Active metasurfaces for manipulatable terahertz technology Jing-Yuan Wu(吴静远), Xiao-Feng Xu(徐晓峰), Lian-Fu Wei(韦联福) Chin. Phys. B, 2020, 29 (9): 094202.   DOI: 10.1088/1674-1056/aba613 Abstract （661）   HTML    PDF （5175KB）（239）       Knowledge map    Metasurface is a kind of two-dimensional metamaterial with specially designed sub-wavelength unit cells. It consists of single-layer or few-layer stacks of planar structures and possesses certain superior abilities to manipulate the propagating electromagnetic waves, including the terahertz (THz) ones. Compared with the usual passive THz metasurfaces whose optical properties are difficult to be controlled after fabrication, the active materials are highly desirable to enable dynamic and tunable control of THz waves. In this review, we briefly summarize the progress of active THz metasurfaces, from their physical mechanisms on carrier concentration modulations, phase transitions, magneto-optical effects, etc., for various possible THz applications mainly with low-dimensional materials, vanadium dioxide films, and superconductors. Select Recent advances in generation of terahertz vortex beams andtheir applications Honggeng Wang(王弘耿), Qiying Song(宋其迎), Yi Cai(蔡懿), Qinggang Lin(林庆钢), Xiaowei Lu(陆小微), Huangcheng Shangguan(上官煌城), Yuexia Ai(艾月霞), Shixiang Xu(徐世祥) Chin. Phys. B, 2020, 29 (9): 097404.   DOI: 10.1088/1674-1056/aba2df Abstract （585）   HTML    PDF （6537KB）（295）       Knowledge map    Last decade has witnessed a rapid development of the generation of terahertz (THz) vortex beams as well as their wide applications, mainly due to their unique combination characteristics of regular THz radiation and orbital angular momentum (OAM). Here we have reviewed the ways to generate THz vortex beams by two representative scenarios, i.e., THz wavefront modulation via specific devices, and direct excitation of the helicity of THz vortex beams. The former is similar to those wavefront engineering devices in the optical and infrared (IR) domain, but just with suitable THz materials, while the latter is newly-developed in THz regime and some of the physical mechanisms still have not been explained explicitly enough though, which would provide both challenges and opportunities for THz vortex beam generation. As for their applications, thanks to the recent development of THz optics and singular optics, THz vortex beams have potentials to open doors towards a myriad of practice applications in many fields. Besides, some representative potential applications are evaluated such as THz wireless communication, THz super-resolution imaging, manipulating chiral matters, accelerating electron bunches, and detecting astrophysical sources. Select Research progress in terahertz quantum-cascade lasers and quantum-well photodetectors Zhi-Yong Tan(谭智勇), Wen-Jian Wan(万文坚), Jun-Cheng Cao(曹俊诚) Chin. Phys. B, 2020, 29 (8): 084212.   DOI: 10.1088/1674-1056/aba945 Abstract （574）   HTML    PDF （836KB）（220）       Knowledge map    As semiconductor devices, the terahertz quantum-cascade laser is a coherent source based on intersubband transitions of unipolar carriers while the terahertz quantum-well photodetector is a kind of detector which matches the laser frequency. They are solid-state, electrically operated, and can be easily integrated with other components. This paper reviews the state of the art for the design, working performance, and future directions of the two devices. Their applications in photoelectric characterization and imaging are also discussed. Select Recent progress in graphene terahertz modulators Xieyu Chen(陈勰宇), Zhen Tian(田震), Quan Li(李泉), Shaoxian Li(李绍限), Xueqian Zhang(张学迁), Chunmei Ouyang(欧阳春梅), Jianqiang Gu(谷建强), Jiaguang Han(韩家广), Weili Zhang(张伟力) Chin. Phys. B, 2020, 29 (7): 077803.   DOI: 10.1088/1674-1056/ab9433 Abstract （557）   HTML    PDF （3540KB）（289）       Knowledge map    Graphene has been recognized as a promising candidate in developing tunable terahertz (THz) functional devices due to its excellent optical and electronic properties, such as high carrier mobility and tunable conductivity. Here, we review graphene-based THz modulators we have recently developed. First, the optical properties of graphene are discussed. Then, graphene THz modulators realized by different methods, such as gate voltage, optical pump, and nonlinear response of graphene are presented. Finally, challenges and prospective of graphene THz modulators are also discussed.