https://doi.org/10.1140/epjd/s10053-024-00943-2
Regular Article - Optical Phenomena and Photonics
Enhanced circular dichroism induced by connectivity effect of rectangular metal nanorods
1
School of Physical Science and Technology, Kunming University, 650214, Kunming, Yunnan, China
2
Key Laboratory of Artificial Microstructures in Yunnan Higher Education Institutions, Kunming University, 650214, Kunming, Yunnan, China
Received:
27
June
2024
Accepted:
27
November
2024
Published online:
21
January
2025
Compared to natural chiral structures, planar chiral plasmonic nanostructures, which are two-dimensional artificial structures composed of noble metals that break mirror symmetry, are widely applied in fields such as analytical chemistry, pharmaceutical production, and bioanalytical monitoring. Understanding circular dichroism (CD) and its enhancement mechanisms is crucial for these applications. Although a variety of chiral structures have been extensively studied, a deep understanding of the tunability of the CD effect remains insufficient. In particular, helical structures face challenges such as difficult fabrication and poor tunability. In this study, we designed a chiral structure composed of rectangular metal nanorods and metallic spheres, aiming to achieve a significant tunable CD effect by utilizing the connectivity effect of the metal nanorods, reaching an impressive CD value of 0.7. Results calculated by the finite element method show that, near the resonant wavelengths of 710 nm and 730 nm, the spectral responses of 
and 
, respectively, exhibit peak and valley patterns, thereby generating a substantial CD effect. Fundamentally, this is due to the shifting of the resonance modes at these specific wavelengths under RCP and LCP light. The extent of this shift can be precisely manipulated by altering the width of the rectangular metal nanorods, thus enabling controlled CD effects. Moreover, the CD effect is found to be highly dependent upon the geometric parameters of the designed structures. In summary, these findings contribute significantly to the development of planar chiral plasmonic nanostructures with tunable and large CD effects, providing valuable insights for their optimization and practical applications.
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Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
