Abstract-Anomalous Terahertz Reflection and Scattering by Flexible and Conformal Coding Metamaterials

1. Lanju Liang¹, 
2. Meiqing Qi², 
3. Jing Yang³,
4. Xiaopeng Shen², 
5. Jiquan Zhai¹, 
6. Weizong Xu⁴, 
7. Biaobing Jin^1,5,*, 
8. Weiwei Liu^3,5,*,
9. Yijun Feng⁴, 
10. Caihong Zhang¹, 
11. Hai Lu⁴,
12. Hou-Tong Chen⁶, 
13. Lin Kang¹, 
14. Weiwei Xu¹,
15. Jian Chen^1,5, 
16. Tie Jun Cui^2,5,*, 
17. Peiheng Wu¹ and
18. Shenggang Liu^5,7

Article first published online: 30 JUN 2015

http://onlinelibrary.wiley.com/doi/10.1002/adom.201500206/abstract;jsessionid=75D9087BA4464D14DC4C0EA2F158CD85.f03t01?userIsAuthenticated=false&deniedAccessCustomisedMessage=

DOI: 10.1002/adom.201500206

© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Arbitrary control of terahertz (THz) waves remains a significant challenge although it promises many important applications. Here, a method to tailor the reflection and scattering of THz waves in an anomalous manner by using 1-bit coding metamaterials is presented. Specific coding sequences result in various THz far-field reflection and scattering patterns, ranging from a single beam to two, three, and numerous beams, which depart obviously from the ordinary Snell's law of reflection. By optimizing the coding sequences, a wideband THz thin film metamaterial with extremely low specular reflection, due to the scattering of the incident wave into various directions, is demonstrated. As a result, the reflection from a flat and flexible metamaterial can be nearly uniformly distributed in the half space with small intensity at each specific direction, manifesting a diffuse reflection from a rough surface. Both simulation and experimental results show that a reflectivity less than −10 dB is achieved over a wide frequency range from 0.8 to 1.4 THz, and it is insensitive to the polarization of the incident wave. This work reveals new opportunities arising from coding metamaterials in effective manipulation of THz wave propagation and may offer widespread applications.

Abstract-A combined system for efficient excitation and capture of LSP resonances and flexible control of SPP transmissions

Zhen Liao, Xiaopeng Shen, Bai Cao Pan, Jie Zhao, Yu Luo and Tie Jun Cui

ACS Photonics

DOI: 10.1021/acsphotonics.5b00096

http://pubs.acs.org/doi/abs/10.1021/acsphotonics.5b00096?journalCode=apchd5

We propose a compact combined system which supports compound spoof surface resonances due to the coupling between spoof surface plasmon polaritons (SPPs) and localized surface plasmons (LSPs). The system is composed of ultrathin metallic spiral structures for discrete LSP resonances and an ultrathin corrugated metallic strip to guide continuous SPP modes. We demonstrate both theoretically and experimentally that the LSP resonances can be efficiently excited and captured by the SPP waveguide, while the SPP transmissions can be judiciously controlled by the LSP structures. The spoof SPP-LSP combined system may find potential applications in sensing and integrated photonic circuitry in the microwave and terahertz frequencies.

Abstract-High-order localized spoof surface plasmon resonances and experimental verifications

• Zhen Liao,
• Yu Luo,
• Antonio I. Fernández-Domínguez,
• Xiaopeng Shen,
• Stefan A. Maier
• & Tie Jun Cui

http://www.nature.com/srep/2015/150410/srep09590/full/srep09590.html

We theoretically demonstrated and experimentally verified high-order radial spoof localized surface plasmon resonances supported by textured metal particles. Through an effective medium theory and exact numerical simulations, we show the emergence of these geometrically-originated electromagnetic modes at microwave frequencies. The occurrence of high-order radial spoof plasmon resonances is experimentally verified in ultrathin disks. Their spectral and near-field properties are characterized experimentally, showing an excellent agreement with theoretical predictions. Our findings shed light into the nature of spoof localized surface plasmons, and open the way to the design of broadband plasmonic devices able to operate at very different frequency regimes.