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Proceedings Paper

Active control properties and coupling effect in the terahertz metamaterials
Author(s): Ji Qi; Zhengyan Liu; Hongru Ma; Chenxin Ding; Pujing Zhang; Qingli Zhou; Cunlin Zhang
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Paper Abstract

We modulate the electromagnetic response of terahertz metamaterials by exciting photogenerated carriers with ultra-short pulsed laser, and realize the active control of terahertz transmission and resonances in a wide band. The experimental results show that when the terahertz electric vector is perpendicular and parallel to the bar direction with the open gap in the circular split ring resonators, respectively, the transmission of the non-resonant region and resonance absorption are significantly tuned by the irradiated pump pulse. With the increase of the pump power, the resonance absorption peak decreases and the frequency of resonance dip has a remarkable blue-shift. Meanwhile, the transmission of the non-resonant region decreases correspondingly. It is also found that the blue-shift of the resonance is mainly determined by the change of conductivity and dielectric constant in the photoexcited layer of the substrate. Through the numerical simulation, we have further proved the introduction of pump light has a significant modulation effect on the electromagnetic properties of terahertz metamaterials. Additionally, it can be observed that the LC resonance annihilates earlier than the resonance of the dipole resonance with the increase of pump power, implying the former is particularly sensitive to the variation of the active control. In the theoretical analysis, based on the Lorenz oscillator model, we have derived and calculated the resonance response intensity of the coupled oscillators under an external field. The calculated results indicate the coupling coefficient and damping rate have an impact on the spectra evolution, showing that the resonant response peak has a remarkable blue-shift with the increase of coupling coefficient and the resonance response intensity decreases with the increase of damping rate.

Paper Details

Date Published: 9 September 2021
PDF: 9 pages
Proc. SPIE 11909, Tenth International Symposium on Ultrafast Phenomena and Terahertz Waves (ISUPTW 2021), 119090R (9 September 2021); doi: 10.1117/12.2605546
Show Author Affiliations
Ji Qi, Capital Normal Univ. (China)
Zhengyan Liu, Capital Normal Univ. (China)
Hongru Ma, Capital Normal Univ. (China)
Chenxin Ding, Capital Normal Univ. (China)
Pujing Zhang, Capital Normal Univ. (China)
Qingli Zhou, Capital Normal Univ. (China)
Cunlin Zhang, Capital Normal Univ. (China)

Published in SPIE Proceedings Vol. 11909:
Tenth International Symposium on Ultrafast Phenomena and Terahertz Waves (ISUPTW 2021)
Liguo Zhu; Xiao Cheng; Daiming Ma, Editor(s)

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