Sunday, July 22, 2018

Abstract-Analytical model of terahertz metasurface for enhanced amplitude modulation


Jiawei Cong,Gaige Zheng, Zhiqiang Zhou,  Min Liu,   Mingyang Chen,  Hongbing Yao, Pengyu Wei,  Naifei Ren

http://iopscience.iop.org/article/10.1088/1361-6463/aad34d

Optically-driven terahertz (THz) modulation generally requires excitation of excessively large photoconductivity of active components, which poses huge challenges for realization and practical applications. With aid of an analytical circuit model, we demonstrate an approach to alleviate the trade-off between large amplitude modulation and use of low photoconductivity in complementary split-ring resonator modulators. As revealed by analytical results and verified by full-wave simulation, the maximum modulation depth and needed photoconductivity are determined by the inductance and gap resistance of the structure, respectively. Therefore, by tailoring its inductance and resistance via geometry adjustment, both improvement of modulation efficiency and reduction of photoconductivity are simultaneously realized. A large amplitude modulation ~0.5 is achieved with ultralow conductivity of 2000S/m. The proposed approach might offer a guideline for structure design of THz devices with various active components.

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