Quasi-Bound State in the Continuum-Driven Co-Frequency Polarization-Multiplexed Tunable Terahertz All Dielectric Metasurface
- 1Air and Missile Defense College, Air Force Engineering University, Xi’an 710051, China
- 2School of Electronics and Information Engineering, Anhui University, Hefei 230601, China
Abstract
Quasi-bound states in the continuum (q-BICs) provide an effective approach for achieving strongly confined resonances in metasurfaces. However, the simultaneous realization of high-Q, polarization-multiplexed, and tunable resonances at a single frequency using a single resonant meta-atom remains challenging. Here, we numerically design and investigate a tunable all-dielectric terahertz (THz) metasurface consisting of a single asymmetric germanium (Ge) resonator by employing COMSOL Multiphysics. By introducing only one asymmetry parameter, the symmetry-protected BIC is transformed into a radiative q-BIC under two orthogonal linear polarizations. Through the coupling between the q-BIC and the intrinsic resonant mode, distinct interference responses are generated. Specifically, at the same frequency of 1.227 THz, a Fano resonance (Q = 606) is obtained under TE polarization, whereas an electromagnetically induced transparency (EIT)-like resonance (Q = 1105) appears under TM polarization. Owing to the tunable property of Ge, the two resonances can be actively modulated, achieving modulation depths of 96.7% and 99.1%, respectively. Furthermore, under TM polarization, the group delay can be continuously tuned from 0 to 259 ps by controlling the Ge conductivity. The proposed metasurface provides a compact platform for polarization-multiplexed and dynamically tunable THz photonic devices.
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BibTeX
@article{zhao2026quasibound,
title = {{Quasi-Bound State in the Continuum-Driven Co-Frequency Polarization-Multiplexed Tunable Terahertz All Dielectric Metasurface}},
author = {Xilai Zhao and Jiahe Wang and Yifang Yuan and Jiangang Liang},
journal = {Nanomaterials (Basel, Switzerland)},
year = {2026},
month = oct,
doi = {10.3390/nano16191257},
url = {https://europepmc.org/article/PMC/PMC13667029},
note = {CC BY},
}
RIS
TY - JOUR
TI - Quasi-Bound State in the Continuum-Driven Co-Frequency Polarization-Multiplexed Tunable Terahertz All Dielectric Metasurface
AU - Xilai Zhao
AU - Jiahe Wang
AU - Yifang Yuan
AU - Jiangang Liang
PY - 2026
DA - 2026/10/01
JO - Nanomaterials (Basel, Switzerland)
DO - 10.3390/nano16191257
UR - https://europepmc.org/article/PMC/PMC13667029
AB - Quasi-bound states in the continuum (q-BICs) provide an effective approach for achieving strongly confined resonances in metasurfaces. However, the simultaneous realization of high-Q, polarization-multiplexed, and tunable resonances at a single frequency using a single resonant meta-atom remains challenging. Here, we numerically design and investigate a tunable all-dielectric terahertz (THz) metasurface consisting of a single asymmetric germanium (Ge) resonator by employing COMSOL Multiphysics. By introducing only one asymmetry parameter, the symmetry-protected BIC is transformed into a radiative q-BIC under two orthogonal linear polarizations. Through the coupling between the q-BIC and the intrinsic resonant mode, distinct interference responses are generated. Specifically, at the same frequency of 1.227 THz, a Fano resonance (Q = 606) is obtained under TE polarization, whereas an electromagnetically induced transparency (EIT)-like resonance (Q = 1105) appears under TM polarization. Owing to the tunable property of Ge, the two resonances can be actively modulated, achieving modulation depths of 96.7% and 99.1%, respectively. Furthermore, under TM polarization, the group delay can be continuously tuned from 0 to 259 ps by controlling the Ge conductivity. The proposed metasurface provides a compact platform for polarization-multiplexed and dynamically tunable THz photonic devices.
SN - 2079-4991
ER -