Abstract-Tunable Ultra-Narrowband Terahertz Perfect Absorber by Using Metal-Insulator-Metal Microstructures

Ruijia  Xu, Xiaoyan Liu, Yu-Sheng Lin,



https://www.sciencedirect.com/science/article/pii/S2211379719300993

An ultra-narrowband terahertz (THz) perfect absorber with metal-insulator-metal (PA-MIM) microstructures is presented. MIM microstructures is composed of Al disk on SiO2/Al/Si substrate. This MIM configuration will induce dipole-image interaction and cause an electromagnetic confinement between MIM microstructures to eliminate the reflection. Therefore, the design of MIM can absorb most of THz wave to realize the THz PA. The absorption intensity of proposed device could be reached 99% with an ultra-high Q-factor of 143. By modifying the gap between top and bottom Al disks of MIM, the electromagnetic response can be tuned from single-band to dual-band resonance. These resonances can be actively controlled the corresponding absorption intensities to possess tunability in application of THz switch and THz variable optical attenuator (VOA). This tunable ultra-narrowband THz PA-MIM paves a way to be an important role in THz applications, such as sensors, detectors, solar cells, coherent thermal emitters and so on.

Abstract-Ultra-broadband terahertz perfect absorber by exciting multi-order diffractions in a double-layered grating structure

Ultra-broadband terahertz perfect absorber by exciting multi-order diffractions in a double-layered grating structure Yan Peng, XiaoFei Zang, YiMing Zhu, Cheng Shi, Lin Chen, Bin Cai, and SongLin Zhuang  »View Author Affiliations

http://www.opticsinfobase.org/oe/abstract.cfm?uri=oe-23-3-2032

Optics Express, Vol. 23, Issue 3, pp. 2032-2039 (2015)
http://dx.doi.org/10.1364/OE.23.002032

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Terahertz (THz) perfect absorber, as a useful functional device, has attracted considerable attention. Traditional metamaterial perfect absorbers are usually in response to single-frequency or multi-frequency owing to the resonance features of the metal-based sub-wavelength structure. In this paper, a simple double-layered doped-silicon grating structure was designed to realize an ultra-broadband and polarization-independent THz perfect absorber. Both theoretical and experimental results demonstrate that the incident THz waves ranging from 0.59 to 2.58 THz can be efficiently absorbed with an absorptivity of more than 95% and a bandwidth of about 2.0 THz. The excellent characteristic of this broad-bandwidth THz perfect absorber is mainly resulted from the air gap mode resonance together with the first-order and the second-order grating diffractions.

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