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.
Surface plasmon polaritons (SPPs) lasing requires population inversion, it is inefficient and possesses poor spectral properties. We develop an inversion-less concept for a quantum plasmonic waveguide that exploits unidirectional superradiant SPP (SSPP) emission of radiation to produce intense coherent surface plasmon beams. Our scheme includes a resonantly driven cold atomic medium in a lossless dielectric situated above an ultra-low loss negative index metamaterial (NIMM) layer. We propose generating unidirectional superradiant radiation of the plasmonic field within an atomic medium and a NIMM layer interface and achieve amplified SPPs by introducing phase-match between the superradiant SPP wave and coupled laser fields. We also establish a parametric resonance between the weak modulated plasmonic field and the collective oscillations of the atomic ensemble, thereby suppressing decoherence of the stably amplified directional polaritonic mode. Our method incorporates the quantum gain of the atomic medium to obtain sufficient conditions for coherent amplification of superradiant SPP waves, and we explore this method to quantum dynamics of the atomic medium being coupled with the weak polaritonic waves. Our waveguide configuration acts as a surface plasmon laser and quantum plasmonic transistor and opens prospects for designing controllable nano-scale lasers for quantum and nano-photonic applications.
The spontaneous emission properties of a two-level emitter embedded in a negative permeability slab near the interface between a negative permeability slab and a negative permittivity slab are investigated. When the impedances of the two slabs are matched and the dissipation of the material is small, the structure forms a very good single-mode cavity for surface plasmons. The extremely high local density of states of surface plasmons results in ultrastrong coupling between the atom and the surface plasmons, and then large vacuum Rabi frequency. A damped vacuum Rabi oscillation occurs in the dynamic evolution of the excited atom close to the interface. The atomic emission spectrum displays an asymmetric two-peak structure with the peak separation equal to the vacuum Rabi frequency.