Abstract-Curved terahertz surface plasmonic waveguide devices

Mingrui Yuan, Yongchang Lu, Ying Zhang, Ziying Zhang, Yanfeng Li, Hongchao Liu, Xixiang Zhang, Jiaguang Han, Weili Zhang,

Structure and dispersion relation. (a) Schematic diagram and geometric parameters of the structure (the red arrow depicts the propagation direction of SPPs). The lower left inset shows the SEM image of the fabricated arc-shaped curved hole array excitation region as well as the fan-shaped coupling region. The lower right inset shows the fabricated waveguide structure. (b) The simulated dispersion relation (red line) of SPP mode for one row of metal pillars.

https://www.osapublishing.org/oe/abstract.cfm?URI=oe-28-2-1987

Strongly confined surface waves can be achieved on periodically structured metal surfaces and are known as spoof surface plasmon polaritons (SPPs). In this work, several terahertz SPP devices based on curved waveguides are demonstrated. The transmittance and bending loss of 90-degree curved spoof SPP waveguides with a radius of curvature ranging from 200 to 2300 µm are investigated to identify the regime for high transmission. A commutator is designed and experimentally demonstrated. Furthermore, coupling equations are derived and verified for efficient coupling between bend-straight waveguides and between bend-bend waveguides. The results will be of great value for future integrated terahertz plasmonic systems.

© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Abstract-High-performance and compact broadband terahertz plasmonic waveguide intersection

Mingrui Yuan, Yanfeng Li, Yongchang Lu, Ying Zhang, Ziying Zhang, Xueqian Zhang, Xixiang Zhang, Jiaguang Hah, Weili Zhang

THz plasmonic waveguides ...

iopscience.iop.org

https://www.degruyter.com/view/j/nanoph.2019.8.issue-10/nanoph-2019-0191/nanoph-2019-0191.pdf

For terahertz (THz) integrated systems, an intersection between waveguides is inevitable and is often accompanied by considerable crosstalk and loss. Here, we propose and experimentally demonstrate a novel type of crossing with a footprint less than 0.2 × 0.2  mm2 for THz surface plasmon polariton waveguiding. With an optimized crossover structure, the measured loss of the intersection is as low as 0.89 dB/crossing, and the crosstalk is less than −19.06 dB/crossing at 0.55 THz. The proposed crossing structure is compact and has low loss and crosstalk within a broad band, which will pave the way for a wide range of new applications for THz integrated systems.

Abstract-Terahertz metamaterial beam splitters based on untraditional coding scheme

Xiaohua Xing, Yanfeng Li, Yongchang Lu, Wentao Zhang, Xixiang Zhang, Jiaguang Han, and Weili Zhang

 (a) Conventional coding “000111000111……/000111000111……” sequence, with “0” elements in blue and “1” elements in yellow. (b) Unconventional “offset” coding sequence. (c) Equivalent modeling of “offset” sequence. (d) Equivalent structure of “offset” sequence for (b). (e) Schematic diagram of θ and φ in the Cartesian coordinate system.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-27-20-A1627

Terahertz waves have attracted considerable research interest in recent years because of their potential applications in diverse fields. As an important device to control terahertz waves, beam splitters with greater flexibility and higher degrees of freedom are highly desirable. In order to obtain higher degrees of freedom in beam splitting, 2-bit or higher-bit coding elements are usually introduced into metamaterial beam splitters based on the coding theory. In this work, a new “offset” coding scheme using only the 1-bit coding elements of “0” and “1” is presented, and the period of coding for beam splitting can be a non-integer multiple of the length of a single unit rather than only its integer multiples. Therefore, more beam-splitting degrees of freedom can be obtained, and the design strategy is experimentally verified. We believe that the new coding scheme will also be of significance in radar cross section reduction and flexible wave control.

© 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement