Plasmon–Exciton Coupling Using DNA Templates

Abstract

Coherent energy exchange between plasmons and excitons is a phenomenon that arises in the strong coupling regime resulting in distinct hybrid states. The DNA-origami technique provides an ideal framework to custom-tune plasmon-exciton nanostructures. By employing this well controlled self-assembly process, we realized hybrid states by precisely positioning metallic nanoparticles in a defined spatial arrangement with fixed nanometer-sized interparticle spacing. Varying the nanoparticle diameter between 30 nm and 60 nm while keeping their separation distance constant allowed us to precisely adjust the plasmon resonance of the structure to accurately match the energy frequency of a J-aggregate exciton. With this system we obtained strong plasmon-exciton coupling and studied far-field scattering at the single-structure level. The individual structures displayed normal mode splitting up to 170 meV. The plasmon tunability and the strong field confinement attained with nanodimers on DNA-origami renders an ideal tool to bottom-up assembly plasmon-exciton systems operating at room temperature.

DNA‐Mediated Self‐Assembly of Plasmonic Antennas with a Single Quantum Dot in the Hot Spot

“…The assembly of the control dimers is mediated by a two‐layer DNA origami sheet, which determines the width of the gap (cf. our previous work and Note S8, Supporting Information). As expected, none of the control structures showed any emission (Figure S13, Supporting Information).…”

“…Dark‐Field Microscopy : All DF measurements were performed with a custom‐built setup and procedure as thoroughly described in Roller et al The signal from each structure was acquired for 60 s in full CCD mode. After isolating the pixels corresponding to the signal of the structure, the corresponding background (adjacent pixels) was subtracted from the signal and normalized using a white Lambertian standard (Spectralon SRS‐99, Labsphere).…”

Dipolar and quadrupolar excitons coupled to a nanoparticle-on-mirror cavity

“…[45], we show that Eq. (20), restricted to the first excitation manifold and in the limit of low pumping (E L → 0), reproduces σ sca for bare NPoM cavities. After a brief description of our calculation of far-field spectra, we investigate next the scattering properties of the QE-SP hybrid systems considered in Sec.…”

“…Orange dashed line plots the same spectrum but considering only the lowest SP and the pseudomode in the evaluation of Eq. (20). The position of the doublet is the same as in the full calculation but, once again, the asymmetry in the peaks height has vanished.…”

New degrees of freedom in nonlinear metamaterials

“…Most recently, spectacular advances of DNA‐origami have been applied toward metamaterial design, with simple arrangements with metallic nanoparticles have been already demonstrated , some of which are even capable of photochemically controllable reconfiguration . These techniques may eventually enable artificial molecular machines with adjustable effective dielectric properties , which would be more robust across changing experimental conditions than natural ones .…”