3-Dimensional folded nanorod chiral structure with broadband circular dichroism response

Structures that cannot coincide with their mirror image are called chiral structures, and artificial chiral structures based on plasmonic metamaterials have a wide range of applications, such as chiral sensing and biometrics. Simple methods to prepare chiral nanostructures capable of producing broadband circular dichroism (CD) effects remain a challenge. Herein, a folded nanorod structure is proposed, which is simple to prepare, low-cost and inherits the chiral advantages of three-dimensional structures. The nanostructures are prepared by oblique angle deposition (OAD) technique, where Ag nanorod, SiO2 nanorod and Ag nanorod are deposited at different azimuthal angles (φ) with a fixed oblique angle (θ). The CD spectra of the structures are measured experimentally and the physical origin of CD was elucidated with the aid of the finite difference time domain method (FDTD). The results show that the structure has a broadband CD response in the band of 650–950 nm. All these advantages make the structure possess the potential to be a low-cost and high-performance chiral sensor device.