A full quantum model incorporating realizable materials properties is developed for interactions between a plasmonic resonator and a single two-level quantum emitter, enabling fabrication of plasmonic nanostructures for the strong coupling regime of cavity-quantum-electrodynamics.
The quantum control of emitters is a key issue for quantum information processing at the nanoscale. This generally necessitates the strong coupling of emitters to a high Q-cavity for efficient manipulation of the atoms and field dynamics (cavity quantum electrodynamics or cQED). Since almost a decade, strong efforts are put to transpose cQED concepts to plasmonics in order to profit of the strong mode confinement of surface plasmons polaritons. Despite the intrinsic presence of lossy channels leading to strong decoherence in plasmonics systems, it has been experimentally proven that it is possible to reach the strong coupling regim [1].
Controlling quantum emitters (atoms, molecules, quantum dots, etc.), light, and its interactionsis a key issue for implementing all-optical devices and information processing at thequantum level. This generally necessitates a strong coupling of emitters to photonic modes,as achieved by a high-Q cavity, for efficient manipulation of the atoms and field dynamicsthrough cavity quantum electrodynamics (cQED).The integration of the principles of quantum optics at the nanoscale in a plasmonic platformhas been envisioned, on the basis of a possible strong coupling between a quantum emitter andthe surface plasmon polaritons (SPPs) via their strong mode confinement. Recent progressshowed the possibility to reach such a strong coupling regime, allowing the development ofquantum plasmonics where a SPP mode takes the role of the cavity mode. However, its applicationappears notoriously limited in practical situations due to the intrinsic presence ofnumerous and lossy modes, which complicates the description and the interpretation of theinteraction, and introduces strong decoherence in the system, in particular for strong coupling.In this work, a detailed overview of quantum control applied to ion trapping, cQED, and plasmonics,is presented. The first part of the thesis is a study of adiabatic processes in trappedion systems and cQED:- We summarize quantum computation processes using quantum gates, and control usingadiabatic laser pulses with atomic systems.- We design arbitrary quantum gates with ions manipulated with laser pulses.- Models for cQED are derived and applied for the production of photon states leakingfrom a cavity.In the second part, we develop a formalism to describe the quantum dynamics of emitters closeto nanoscale structures, and numerics showing the strong coupling regime and the couplingof emitters via plasmon modes. More specifically:- We provide a general field quantization procedure for spherically layered systems.- Effective models using the field quantization are derived, and we show they are analogousto cQED models.- We describe the interaction of localized plasmons (LSPs) with quantum emitters.- The coupling/entanglement of emitters by adiabatic passage through lossy plasmonicmodes of a nanosphere is shown.
Quantum plasmonics extends cavity quantum electrodynamics (cQED) concepts to the nanoscale, benefiting from the strongly subwavelength confinement of the plasmon modes supported by metal nanostructures. In this work, we describe in detail collective strong coupling to a plasmonic nanocavity. Similarities and differences to cQED are emphasized. We notably observe that the Rabi splitting can strongly deviate from the standard NeΔΩ1 law, where Ne is the number of emitters and ΔΩ1 is the Rabi splitting for a single emitter. In addition, we discuss the collective Lamb shift and the role of quantum corrections to the emission spectra.
The strong confined electromagnetic field in the micro/nano photonic structures brings new opportunities for the research of interaction between light and matter. By designing optical modes, light can be controlled to realize reversible or inreversible energy exchange between photons and emitters at the micro/nano scale. Here, we review the basic principles of the interaction between light and matter in cavity quantum electrodynamics and their recent advances in strong coupling based on micro/nano photonic structures such as plasmon nanostructures, whispering gallery resonators and photonic crystals. These works opening the research of quantum nanophotonics will have great influence on the on-chip quantum devices and quantum informations.
Plasmons in nanostructured metals are widely utilized to trigger strong light-matter interactions with quantum light sources. While the nonclassical behavior of such quantum emitters (QEs) is well understood in this context, the role of quantum and surface effects in the plasmonic resonator is usually neglected. Here, we combine the Green's tensor approach with the Feibelman d-parameter formalism to theoretically explore the influence of quantum surface effects in metal-dielectric layered nanostructures on the relaxation dynamics of a proximal two-level QE. Having identified electron spill-out as the dominant source of quantum effects in jellium-like metals, we focus our study on sodium. Our results reveal a clear splitting in the emission spectrum, indicative of having reached the strong coupling regime, and, more importantly, non-Markovian relaxation dynamics of the emitter. Our findings establish that strong light-matter coupling is not suppressed by the emergence of nonclassical surface effects in the optical response of the metal.
Here we present the theoretical foundation of the strong coupling phenomenon between quantum emitters and propagating surface plasmons observed in two-dimensional metal surfaces. For that purpose, we develop a quantum framework that accounts for the coherent coupling between emitters and surface plasmons and incorporates the presence of dissipation and dephasing. Our formalism is able to reveal the key physical mechanisms that explain the reported phenomenology and also determine the physical parameters that optimize the strong coupling. A discussion regarding the classical or quantum nature of this phenomenon is also presented.