scholarly journals Passively Tunable Terahertz Filters Using Liquid Crystal Cells Coated with Metamaterials

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 381
Author(s):  
Wei-Fan Chiang ◽  
Yu-Yun Lu ◽  
Yin-Pei Chen ◽  
Xin-Yu Lin ◽  
Tsong-Shin Lim ◽  
...  

Liquid crystal (LC) cells that are coated with metamaterials are fabricated in this work. The LC directors in the cells are aligned by rubbed polyimide layers, and make angles θ of 0°, 45°, and 90° with respect to the gaps of the split-ring resonators (SRRs) of the metamaterials. Experimental results display that the resonance frequencies of the metamaterials in these cells increase with an increase in θ, and the cells have a maximum frequency shifting region of 18 GHz. Simulated results reveal that the increase in the resonance frequencies arises from the birefringence of the LC, and the LC has a birefringence of 0.15 in the terahertz region. The resonance frequencies of the metamaterials are shifted by the rubbing directions of the polyimide layers, so the LC cells coated with the metamaterials are passively tunable terahertz filters. The passively tunable terahertz filters exhibit promising applications on terahertz communication, terahertz sensing, and terahertz imaging.

Crystals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1100
Author(s):  
Yi-Hong Shih ◽  
Xin-Yu Lin ◽  
Harry Miyosi Silalahi ◽  
Chia-Rong Lee ◽  
Chia-Yi Huang

An optically tunable terahertz filter was fabricated using a metasurface-imbedded liquid crystal (LC) cell with photoalignment layers in this work. The LC director in the cell is aligned by a pump beam and makes angles θ of 0, 30, 60 and 90° with respect to the gaps of the split-ring resonators (SRRs) of the metasurface under various polarized directions of the pump beam. Experimental results display that the resonance frequency of the metasurface in the cell increases with an increase in θ, and the cell has a frequency tuning region of 15 GHz. Simulated results reveal that the increase in the resonance frequency arises from the birefringence of the LC, and the LC has a birefringence of 0.13 in the terahertz region. The resonance frequency of the metasurface is shifted using the pump beam, so the metasurface-imbedded LC cell with the photoalignment layers is an optically tunable terahertz filter. The optically tunable terahertz filter is promising for applications in terahertz telecommunication, biosensing and terahertz imaging.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Haibin Sun ◽  
Cai Feng ◽  
Yongjun Huang ◽  
Ruiming Wen ◽  
Jian Li ◽  
...  

A novel dual-band rectangular waveguide notch filter is experimentally investigated in this paper. Such filter is realized by integrating two pairs of split ring resonators (SRRs) printed on the two sides of a dielectric slab with twist angles and separated as a distance in the center of the rectangular waveguide. Due to the coupling effects between the twist SRRs and between the original SRRs and their mirror images generated by the metallic walls perpendicular to the E-field direction, it can flexibly contribute two disjunct resonance states and result in the dual-band notch properties. Furthermore, the two resonance frequencies can be controlled by changing the twist angles, resulting in the shifts of notch frequency bands.


2013 ◽  
Vol 138 ◽  
pp. 407-419 ◽  
Author(s):  
Yanbing Ma ◽  
Huai-Wu Zhang ◽  
Yuanxun Li ◽  
Yicheng Wang ◽  
Weien Lai

2019 ◽  
Vol 46 (15) ◽  
pp. 2127-2133
Author(s):  
Chang Ding ◽  
Fan-Yi Meng ◽  
Hui-Lin Mu ◽  
Jian-Qiao Han ◽  
Chuan-Hong Zhao ◽  
...  

2014 ◽  
Vol 39 (5) ◽  
pp. 1129 ◽  
Author(s):  
Bernhard Atorf ◽  
Holger Mühlenbernd ◽  
Mulda Muldarisnur ◽  
Thomas Zentgraf ◽  
Heinz Kitzerow

2006 ◽  
Vol 89 (4) ◽  
pp. 041101 ◽  
Author(s):  
B. G. Quan ◽  
X. L. Xu ◽  
H. F. Yang ◽  
X. X. Xia ◽  
Q. Wang ◽  
...  

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