Exceptional points and lines and Dirac points and lines in magnetoactive cholesteric liquid crystals

Gevorgyan, A.H.

doi:10.1016/j.molliq.2023.123180

Cited by 8 publications

(1 citation statement)

References 65 publications

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“…In 2023, A.H. Gevorgyan studied the characteristics of cholesteric liquid crystals (CLCs) in an external static magnetic field oriented along the helical axis, demonstrating the appearance of Dirac lines and anomalous lines at specific helical spacings, where there is a broadband spectral region with reflection, transmission, and absorption independent of the polarization of the incident light. In addition, there is a broadband spectral region where complete absorption occurs, independent of the polarization of the incident light [25]. In addition, our team conducted research and published papers on bandwidth-adjustable terahertz functional devices in 2023 and 2024, achieving functions such as broadband absorption, broadband line polarization conversion, and narrowband four-band absorption [26,27].…”

Section: Introductionmentioning

confidence: 99%

Tunable broadband absorption and broadband linear polarization converter based on vanadium dioxide

Niu,

Hui,

et al. 2024

Phys. Scr.

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A composite dielectric metamaterial based on vanadium dioxide (VO2) is proposed to achieve flexible switching between two functions, broadband absorption, and polarization conversion, by adjusting the VO2 conductivity. The designed metamaterial functions as a broadband ab-sorber when VO2 is in the metal phase. The absorber consists of a VO2 top structure, a silicon dioxide (SiO2) dielectric layer, and a VO2 thin film. Numerical simulation ns show that the absorber can absorb up to more than 90% in the frequency range of 3.22~8.51 THz, and due to the symmetry of the structure, the absorber is characterized by polarization-insensitive proper-ties and good absorption over a wider incidence angle. When VO2 is in the insulator phase, the designed metamaterial has a cross-polarization conversion function. The linear polarization converter primarily comprises an I-beam metal, a SiO2 dielectric layer, and a gold substrate layer. Numerical simulations demonstrate that the linear polarization converter accomplishes a line polarization conversion rate (PCR) greater than 90% within the 1.40~4.11 THz frequency range, attains a close to 100% cross-polarization conversion rate (PCR) at 1.46, 1.95, 3.0, and 3.97 THz. To confirm the wave absorption mechanism of the absorber, we utilize the impedance matching theory to analyze it. The proposed switchable bifunctional metamaterials present significant potential for broader applications in future terahertz communication, imaging, stealth technology, and related fields.

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Section: Introductionmentioning

confidence: 99%