Chiral plasmonic
nanostructures (CPNs) with a strong chiroptical
response in visible and near-infrared regions were fabricated with
homemade SiO2 chiral templates through oblique angle deposition.
The circular dichroism spectra of the CPNs showed that the chiroptical
response was amplified with increased deposition thickness of silver.
Simulation results demonstrated that only the magnetic dipole mode
was excited when the deposition thickness was small. Magnetic and
electric dipoles emerged and coupled to each other with increased
silver deposition thickness. As a result, chiroptical enlargement
occurred. This study provides a concise method of fabricating CPNs
with a tunable chiroptical response.
The circular dichroism (CD) effect characterized by different optical responses between left and right circularly polarized lights is widely applied for polarization-resolved detection and imaging. The tunable CD effect is of substantial importance in improving the detection sensitivity and imaging resolution. In this paper, we show that planar Z-shaped composite metamaterial embedded with VO2 that exhibits insulator-metal transition (IMT) can enable thermally tunable chirality. Simulated by the finite element method, the tunable CD effect can be achieved by changing the environment temperature to initiate the IMT of VO2. We also demonstrate that the underlying mechanism of the CD effect generation is the electric multipole oscillation response in the vicinity of the VO2 gap in vertical direction. These findings not only provide a new strategy to change chirality and tune the effect of CD dynamically but also broaden its potential applications in polarization-resolved detection and imaging.
The circular dichroism (CD) effect plays an important role in biological detection, analytical chemistry, and plasmonic sensing. Tilted 3D structures can generate CD signals under normal illumination. However, fabricating tilted 3D structures is complex and expensive. In this study, we fabricate a tilted U-shaped nanostructure (TUSN) on a polystyrene (PS) nanosphere through the glancing angle deposition method. One branch of the U-shaped nanostructure is tilted by raising a sheet of SiO2 on the PS nanosphere. And the CD signal of the TUSN is enhanced because the phase difference increases with increasing thickness of the SiO2 sheet. This work proposes a method for fabricating tilted nanostructures and elucidates the mechanism of the CD effect for future research.
In this paper, a dielectric layer is introduced to tune circular dichroism (CD) of chiral plasmonic metasurfaces. The dielectric layer is used to control the optical phase of electric diploes in Born-Kuhn configurations. To prove our assumption, an L-shaped plasmonic metasurface consisting of two metallic slices is prepared by glancing angle deposition, and then an SiO 2 slice is deposited on one arm of the L-shaped metasurface. Experimental results reveal that CD of the L-shaped plasmonic metasurface can be tuned by the thickness of the SiO 2 slice. These findings not only contribute to a better understanding of the CD physical mechanism, but also can be used in nanophotonic metasurfaces because of the concise fabrication process.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.