Dynamically controlled asymmetric transmission of linearly polarized waves in VO2-integrated Dirac semimetal metamaterials |
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| Affiliation: | 1.College of Electronic and Information Engineering, Shandong University of Science and Technology, Qingdao 266590, China;2.Collaborative Innovation Center of Light Manipulations and Applications, Shandong Normal University, Jinan 250358, China |
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| Abstract: | We numerically demonstrated a novel chiral metamaterial to achieve broadband asymmetric transmission (AT) of linearly polarized electromagnetic waves in terahertz (THz) band. The proposed metamaterial unit cell exhibits no rotational symmetry with vanadium dioxide (VO$_{2}$) inclusion embedded between Dirac semimetals (DSMs) pattern. The resonant frequency of AT can be dynamically tunable by varying the Fermi energy ($E_{\rm F}$) of the DSMs. The insulator-to-metal phase transition of VO$_{2}$ enables the amplitude of the AT to be dynamically tailored. The transmission coefficient $|T_{yx}|$ can be adjusted from 0.756 to nearly 0 by modifying the conductivity of VO$_{2}$. Meanwhile, the AT parameter intensity of linearly polarized incidence can be actively controlled from 0.55 to almost 0, leading to a switch for AT. When VO$_{2}$ is in its insulator state, the proposed device achieves broadband AT parameter greater than 0.5 from 1.21 THz to 1.80 THz with a bandwidth of 0.59 THz. When the incident wave propagates along the backward ($-z$) direction, the cross-polarized transmission $|T_{yx}|$ reaches a peak value 0.756 at 1.32 THz, whereas the value of $|T_{xy}|$ well below 0.157 in the concerned frequency. On the other hand, the co-polarized transmission $|T_{xx}|$ and $|T_{yy}|$ remained equal in the whole frequency range. This work provides a novel approach in developing broadband, tunable, as well as switchable AT electromagnetic devices. |
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| Keywords: | terahertz chiral metamaterials asymmetric transmission tunable |
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