Abstract-Metamaterials absorber based on doped semiconductor for THz and FIR frequency ranges

Miao Chen, Wei Yan, Xin Tong, Liuwen Zeng, Zhaofeng Li,  Fuhua Yang,

http://iopscience.iop.org/article/10.1088/2040-8986/ab00d8/pdf

In this paper, we propose a metamaterials absorber for terahertz and far infrared frequency ranges. The elementary absorber structure consists of one dielectric layer stacked on one doped semiconductor layer without structure patterning. The ideal permittivity of the doped semiconductor layer for achieving perfect absorption is derived based on the impedance transformation method. Since the permittivity of the doped semiconductor can be tuned by doping, the impedance matching condition can be met at wanted frequency range. The simulation results show that the absorption reaches 97% at the impedance matching point. Furthermore, a broadband absorber can be formed by adding one pair of patterned dielectric-doped semiconductor layers on top of the elementary absorber structure. The average absorption of the broadband absorber reaches 95% from 8 THz to 14 THz. The proposed design which is flexible and compatible with semiconductor technology may find its applications in fields such as terahertz detection, imaging and bioanalytics.

Abstract-A Tunable Polarization-Dependent Terahertz Metamaterial Absorber Based on Liquid Crystal

Guangsheng Deng, Yujiao Lu, Zhiping Yin,  Weien Lai, Hongbo Lu,  Jun Yang, Aifeng Yang, Yang Ye, Dayong Liu, Baihong Chi,

http://www.mdpi.com/2079-9292/7/3/27

In this paper, a tunable polarization-dependent terahertz (THz) metamaterial absorber based on liquid crystal (LC) is presented. The measurement results show that absorption peak is at 239.5 GHz for a TE-polarized wave and 306.6 GHz for a TM-polarized wave, without exerting the bias voltage on the LC layer. An increase in bias voltage affects the orientation of LC molecules and causes redshifted resonant frequencies. By adjusting the bias voltage from 0 to 10 V, frequency tunabilities of 4.7% and 4.1% for TE- and TM-polarized waves, respectively, were experimentally demonstrated. Surface current and power loss distribution was analyzed to explain the physical mechanism of the absorber, while the absorption dependence on geometrical parameters and incident angles was also studied in detail. According to the obtained results, the proposed absorber is shown here to be capable of achieving tunable polarization-dependent absorption, and to have potential application in terahertz polarization imaging, terahertz sensing, and polarization multiplexing

Abstract-Simulation of terahertz metamaterial absorbers with microbolometer structure

Jie Ding, Jun Wang, Xiaopei Guo, Yadong Jiang, Lin Fan

Univ. of Electronic Science and Technology of China (China)

http://proceedings.spiedigitallibrary.org/proceeding.aspx?articleid=1902062

Proc. SPIE 9284, 7th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optoelectronics Materials and Devices for Sensing and Imaging, 92841E (September 2, 2014); doi:10.1117/12.2068152

The metamaterial absorber in terahertz (THz) region, with the metal pattern layer/dielectric spacer/metal reflective layer sandwich structure, is characterized in this paper. The principle of metamaterial absorber absorbing terahertz wave was introduced firstly. The top layer of metamaterial absorber is a periodically patterned with metallic subwavelength structure, which also serves as an electric resonator. The bottom layer is a thick metal plane, which is used to reduce THz wave transmittance. The dielectric layer between two metallic layers results in magnetic resonance and the resonance depends on the thickness and dielectric constant of the dielectric layer. The absorption of metamaterial absorber to terahertz wave was simulated with CST software. The relationship between the size of the metamaterial structure and absorption frequency was analyzed with the simulation results. The results indicate that the absorption frequency is affected by the cell constant and geometric structure of top metal pattern, and absorption rate is related to both the thickness of dielectric layer and the size of resonator. In the end, the possibility of integrating the metamaterial absorber with micro-bridge structure to design room temperature terahertz detector was discussed, and the manufacturing process was introduced about room temperature terahertz detector with high THz wave absorption rate.
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