Tunable atom-trapping based on a plasmonic chiral metamaterial

Abstract

Chiral metamaterials provide a very convenient way to actively regulate the light field via external means, which is very important in nanophotonics. However, the very weak chiral response of a generally planar metamaterial severely limits its application. Therefore, it is important to design a system with large circular dichroism. Here we report an optical metamaterial with strong chirality in a bilayer gear-shaped plasmonic structure and consider this chiral response of such fields on tunable atom (87Rb) trapping. Simulation results show that maximum chiral response is observed when the two layers of the gear-shaped structures are rotated from each other by an angle of 60° at λ = 760 nm. Also, we demonstrate an active tunable potential for three-dimensional stable atom-trapping with tunable range of position and potential of a neutral atom of ~58 nm and ~1.3N mK (N denotes the input power with unit mW), respectively. In addition, the trap centers are about hundreds of nanometers away from the structure surface, which ensures the stability of the trapping system. The regulation of neutral atom trapping broadens the application of chiral metamaterials and has potential significance in the manipulation of cold atoms.

Chiral Plasmonics and Their Potential for Point-of-Care Biosensing Applications

“…The main limitation of a geometry-focused approach for chiral plasmonics is that the functionality cannot be easily manipulated post-fabrication. This drawback has motivated research work to fabricate plasmonic nanostructures whose chiroptical properties can be manipulated [55][56][57][58][59][60][61][62][63]. Figure 3 shows the calculated near-field chiral density (Ĉ) for a shuriken-shaped nanostructure [57].…”

Plasmon-Induced Transparency for Tunable Atom Trapping in a Chiral Metamaterial Structure

“…Additionally, surface potential plays an important role in the trapping characteristics when the atom is very close to the surface (within 100 nm) [38,39]. However, in our case, ds is about 300 nm away from the surface, while the surface potential can be neglected in the calculation, which can be attributed to the near-field scattering properties of SPPs [33][34][35]. Therefore, the total potential depends on the optical potential Uopt only, which can be easily tuned through |E| by optimizing the structural parameters.…”

“…Neutral atom trapping plays a vital role in quantum computing and data storage. The minimum value of the local electric field generated by the near-field scattering effect of periodic surface plasmons is the best region to realize the atom trapping with detuned blue light [33][34][35]. Herein, we first unite the PIT phenomenon with atom trapping through the structure proposed in Figure 1a and discuss in detail the PIT effect on the trapping characteristics of neutral atoms.…”

Deep learning for circular dichroism of nanohole arrays

“…Chirality refers to the non-imposition of structures with their mirror ones [1][2][3] and plays a crucial role in chemistry [4], spectroscopy [5], life science [6], medicine [7], and quantum computing [8,9]. Chiral nanostructures show different electromagnetic responses to the absorption and transmission of left circularly polarized (LCP) light and right circularly polarized (RCP) light illumination, and this feature is referred to as circular dichroism (CD) [10][11][12].…”