Tunable circular dichroism of chiral metamaterial based on phase transition of vanadium dioxide (VO₂)

Abstract

The circular dichroism effect characterized by different optical responses between left-handed and right-handed circularly polarized lights is widely applied for biological monitoring, analytical chemistry, and plasmonic sensing. Despite the fact that circular dichroisms are achieved by many conventional chiral and anisotropic metamaterials, dynamic and efficient modulation of circular dichroisms is still challenging. In this paper, we demonstrate a VO 2 embedded metamaterial enabling tunable chirality by taking advantages of the VO 2 phase transitions between insulators and metals. Specifically, by changing the laser power and the irradiated position on the metamaterial, the VO 2 phase transition takes place at the irradiated region and induces a tunable circular dichroism effect. This work provides a strategy for the active control and modulation of circular polarizations, which pays the way for applications in terahertz and microwave regions.

Circular Dichroism Enhancement and Biosensing Application of Composite Dielectric Chiral Nanostructures

“…The corresponding conductivity of VO 2 is σ = 200 S/m in the dielectric state and σ = 10 5 S/m in the mental state. 50 The wavelength-dependent complex dielectric constant of monolayer MoS 2 measured experimentally by Li et al is employed in our simulations. 59 The refractive index of SiO 2 is 1.45.…”

“…Vanadium dioxide (VO 2 ) is a phase change material, a sudden insulator−metal transition (IMT) occurs at a temperature of about 68 °C, resulting in dramatic changes in electromagnetic properties. 50 By the IMT characteristics of VO 2 , the absorption intensity of the nanosystem coupled between the nanostructure and VO 2 can be thermally switched for linearly polarized light 51 and perfect absorption and asymmetric transmission can be thermally switched for circularly polarized light. 52 Hence, the introduction of MoS 2 and VO 2 into our dielectric nanostructures is expected to enhance and dynamically adjust the CD signal of the dielectric nanostructures.…”

“…To improve the absorption, the coupling between the metal nanostructure and the monolayer MoS 2 can significantly improve the absorbance of the nanosystem excited by linearly polarized light. − However, the above methods cannot achieve dynamic adjustment of CD signals. Vanadium dioxide (VO 2 ) is a phase change material, a sudden insulator–metal transition (IMT) occurs at a temperature of about 68 °C, resulting in dramatic changes in electromagnetic properties . By the IMT characteristics of VO 2 , the absorption intensity of the nanosystem coupled between the nanostructure and VO 2 can be thermally switched for linearly polarized light and perfect absorption and asymmetric transmission can be thermally switched for circularly polarized light .…”

An active tunable terahertz functional metamaterial based on hybrid-graphene vanadium dioxide

“…30 By utilizing the phase transition properties of VO 2 , Gao et al numerically and experimentally verified a VO 2 -embedded metamaterial to achieve dynamic control of CD. 31 Ren et al presented a metamaterial device that can switch between perfect absorption and broadband asymmetric transmission. 32 Lv et al designed a switchable dual-band to broadband terahertz metamaterial absorber.…”

Chirality–Racemization Strategy Toward Copper (I) Iodide Hybrid Single‐Crystalline Scintillators for X‐Ray Detection and Imaging Applications

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dichroism (CD), [1][2][3] circularly polarized luminescence (CPL), [4][5][6][7][8] second harmonic generation (SHG), [9][10][11] piezoelectricity, [12,13] ferroelectricity, [14][15][16] and chiral-induced spin selectivity (CISS). [17,18] Chiral hybrid organic-inorganic materials formed by substituting the A-site cations with the chiral organic cations manifest the noncentrosymmetric structures, which enable them exhibit the interesting optoelectronic functionality, such as chiroptics [19][20][21] and chiro-spintronics.

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