Abstract-Terahertz Spoof Surface Plasmonic Logic Gates

 

Mingrui Yuan, Qingwei Wang, Yanfeng Li, Yuehong Xu, Quan Xu, Xueqian Zhang, Xixiang Zhang, Jiaguang Han, Weili Zhang, 

https://www.sciencedirect.com/science/article/pii/S2589004220308774

Logic gates are important components in integrated photonic circuitry. Here, a series of logic gates to achieve fundamental logic operations based on linear interference in spoof surface plasmon polariton waveguides are demonstrated at terahertz frequencies. A metasurface-based plasmonic source is adopted to couple free-space terahertz radiation into surface waves, followed by a funnel-shaped metasurface to efficiently couple the surface waves to the waveguides built on a domino structure. A single Mach-Zehnder waveguide interferometer can work as logic gates for four logic functions: AND, NOT, OR, and XOR. By cascading two such interferometers, NAND and NOR operations can also be achieved. Experimental investigations are supported by numerical simulations, and good agreement is obtained. The logic gates have compact sizes and high intensity contrasts for the output “1” and “0” states. More complicated functions can be envisioned and will be of great value for future terahertz integrated computing.

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.