Abstract-Quad-band linear terahertz frequency conversion in time-varying metasurfaces

Ran Jia,  Li Meihao, Yang Fan, Huang Xin, Yang Qi, Xie Shengyi, Yu Xiao, 



https://www.sciencedirect.com/science/article/abs/pii/S0030401820303345

In this Letter, a quad-band linear frequency conversion prototype is proposed and investigated in terahertz region based on a time-varying metasurface. The unit cell of the metasurface consists of four pairs of concentric split-ring resonators loaded with photoactive silicon. By changing the conductivity of photoactive silicon via optical pump, both static and time-varying metasurfaces are achieved and investigated. Numerical results show that the transmission spectrum of the static metasurface has four merged resonant frequencies at 0.49 THz, 0.58 THz, 0.71 THz, 0.81 THz respectively, and linear frequency conversion appears at these four frequencies under the modulation of time-varying metasurface. The conversion linearity is also verified by applying dual-band bandpass filters with different center frequency. The coefficients of determination are 0.98, 0.94, 0.87, 0.96 correspondingly. This prototype provides a new approach for realizing quad-band frequency conversion for ambient terahertz wave and has wide applications in terahertz imaging and communication systems.

Abstract-Tunable subwavelength terahertz plasmon-induced transparency in the InSb slot waveguide side-coupled with two stub resonators

Tunable subwavelength terahertz plasmon-induced transparency in the InSb slot waveguide side-coupled with two stub resonators Huaiqing Liu, Guobin Ren, Yixiao Gao, Yudong Lian, Yang Qi, and Shuisheng Jian  »View Author Affiliations

Applied Optics, Vol. 54, Issue 13, pp. 3918-3924 (2015)
http://dx.doi.org/10.1364/AO.54.003918

http://www.opticsinfobase.org/ao/abstract.cfm?uri=ao-54-13-3918

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We numerically investigated the realization of electromagnetically induced transparency (EIT) at the terahertz (THz) region in an InSb slot waveguide side-coupled with two stub resonators. The mechanism of the EIT phenomenon is theoretically analyzed and numerically studied by using coupled mode theory and the finite element method, respectively, and the theoretical results are in good agreement with the simulation results. The simulation results reveal that the EIT-like response is strongly dependent on the coupling separation between the two stub resonators, and we derived the best separation between the two stub resonators to get the most obvious EIT-like spectra. More importantly, the central wavelength of the EIT-like spectra can be actively controlled by tuning the temperature. This plasmonic waveguide system may have potential applications for ultracompact THz integrated circuits, such as thermo-tunable filters, THz switching, slow-light components, and THz sensitive sensors.

© 2015 Optical Society of America

Abstract-Tunable subwavelength terahertz plasmon-induced transparency in the InSb slot waveguide side-coupled with two stub resonators

Tunable subwavelength terahertz plasmon-induced transparency in the InSb slot waveguide side-coupled with two stub resonators Huaiqing Liu, Guobin Ren, Yixiao Gao, Yudong Lian, Yang Qi, and Shuisheng Jian  »View Author Affiliations

Applied Optics, Vol. 54, Issue 13, pp. 3918-3924 (2015)
http://dx.doi.org/10.1364/AO.54.003918

http://www.opticsinfobase.org/ao/abstract.cfm?uri=ao-54-13-3826

View Full Text Article

Enhanced HTML    Acrobat PDF (929 KB)

We numerically investigated the realization of electromagnetically induced transparency (EIT) at the terahertz (THz) region in an InSb slot waveguide side-coupled with two stub resonators. The mechanism of the EIT phenomenon is theoretically analyzed and numerically studied by using coupled mode theory and the finite element method, respectively, and the theoretical results are in good agreement with the simulation results. The simulation results reveal that the EIT-like response is strongly dependent on the coupling separation between the two stub resonators, and we derived the best separation between the two stub resonators to get the most obvious EIT-like spectra. More importantly, the central wavelength of the EIT-like spectra can be actively controlled by tuning the temperature. This plasmonic waveguide system may have potential applications for ultracompact THz integrated circuits, such as thermo-tunable filters, THz switching, slow-light components, and THz sensitive sensors.

© 2015 Optical Society of America