Room-Temperature Strong Coupling Between a Single Quantum Dot and a Single Plasmonic Nanoparticle

Abstract

A single quantum dot (QD) strongly coupled with a plasmonic nanoparticle yields a promising qubit for scalable solidstate quantum information processing at room temperature. However, realizing such a strong coupling remains challenging due to the difficulty of spatial overlap of the QD excitons with the plasmonic electric fields (EFs). Here, by using a transmission electron microscope we demonstrate for the first time that this overlap can be realized by integrating a deterministic single QD with a single Au nanorod. When a wedge nanogap cavity consisting of them and the substrate is constructed, the plasmonic EFs can be more effectively "dragged" and highly confined in the QD's nanoshell where the excitons mainly reside. With these advantages, we observed the largest spectral Rabi splitting (reported so far) of ∼234 meV for a single QD strong coupling with plasmons. Our work opens a pathway to the massive construction of roomtemperature strong coupling solid qubits.

Polaritonic Huang–Rhys Factor: Basic Concepts and Quantifying Light–Matter Interactions in Media

“…The blue, green, and red dots correspond to the photonic structures in panel a. × in panel d represents the reported experimental results (Table S2), − showing that the theoretical and the previous experimental results are within one order of magnitude. The following parameters were used in panels b–d: | μ eg | = 10 D and |Δ μ | = 20 D.…”

“…Note that the deviation between theoretical and experimental results ( g and V eff ) originates from different local polaritonic density of states ( Im boldG̅̅ false( boldr normalM , boldr normalM , ω false) ) and μ eg . In other words, the reported μ eg and photonic structures are clearly distinct from the parameters applied in our simulations for simplicity. − The results reveal that our theory can be utilized to predict g and V eff in arbitrary dielectric environments, providing a useful guide for experimentalists to precisely control light–matter interaction and QED effects.…”

“…Based on macroscopic QED, our theory not only provides several useful concepts derived from the polaritonic HR factor S pol , but also offers a quantitative analysis of light–matter interaction in the medium. In Figure , we evaluate S pol , reorganization dipole self-coupling Λ pol , modified light–matter coupling strength g , and effective mode volume V eff in different dielectric environments and further compare the reported light–matter coupling strength in experiments. − Here we investigate three kinds of photonic systems: SiO 2 -coated metal surfaces, SiO 2 -coated metal nanospheres, and metal Fabry–Perot (FP) nanocavities, where the metal species include Au, Ag, Al, and Pt (Figure a). Similar photonic systems showing strong light–matter interactions have been developed in experiments. − Here we use the Fresnel method and Mie theory developed by our previous studies to evaluate the dyadic Green’s functions in planar and spherical systems, respectively. ,, The simulated data of each system are shown in Table S1.…”

Entanglement generation by strong coupling between surface lattice resonance and exciton in an Al nanoarray-coated WS2 quantum emitter

“…As a superposition of quantum states, the entangled state [ 7 ] has attracted much attention due to its nonlocal coherence, which constitutes the basis of quantum cryptography and quantum teleportation [ 8 ]. Furthermore, the room-temperature strong coupling [ 9 ] promotes the generation of entangled states as well.…”

How to Obtain the Correct Rabi Splitting in a Subwavelength Interacting System

“…Such difference in the absorption spectra, i.e., a dip in the plasmon channel and a protrusion in the exciton channel around the exciton resonance, illustrates straightforwardly how “energy transfer” happens irreversibly from the plasmon to the exciton. , In this coupling regime, the energy stored in the exciton material is maximized . In most experimental studies on the coupled plasmon-exciton systems in the single-particle level, ,,,,,− the use of scattering spectroscopy contains predominantly the contribution from the plasmon channel. It therefore yields a suspiciously large Rabi splitting, which is sometimes a pseudo strong coupling.…”