Frontier quantum engineering tasks require reliable control over light-matter interaction dynamics, which could be obtained by introducing electromagnetic structuring. Initiated by the Purcell's discovery of spontaneous emission acceleration in a cavity, the concept of electromagnetic modes' design have gained a considerable amount of attention due to development of photonic crystals, micro-resonators, plasmonic nanostructures and metamaterials. Those approaches, however, offer qualitatively different strategies for tailoring light-matter interactions and are based on either high quality factor modes shaping, near field control, or both. Remarkably, rigorous quantum mechanical description might address those processes in a different fashion. While traditional cavity quantum electrodynamics tools are commonly based on mode decomposition approach, few challenges rise once dispersive and lossy nanostructures, such as noble metals (plasmonic) antennas or metamaterials, are involved. The primary objective of this review is to introduce key methods and techniques while aiming to obtain comprehensive quantum mechanical description of spontaneous, stimulated and higher order emission and interaction processes, tailored by nanostructured material environment. The main challenge and the complexity here are set by the level of rigorousity, up to which materials should be treated. While relatively big nanostructured features (10 nm and larger) could be addressed by applying fluctuation–dissipation theorem and corresponding Green functions' analysis, smaller objects will require individual approach. Effects of material granularity, spatial dispersion, tunneling over small gaps, material memory and others will be reviewed. Quantum phenomena, inspired and tailored by nanostructured environment, plays a key role in development of quantum information devices and related technologies. Rigorous analysis is required for both examination of experimental observations and prediction of new effects.
Frontier quantum engineering tasks require reliable control over light-matter interaction dynamics, which could be obtained by introducing electromagnetic structuring. Initiated by the Purcell's discovery of spontaneous emission acceleration in a cavity, the concept of electromagnetic modes' design have gained a considerable amount of attention due to development of photonic crystals, micro-resonators, plasmonic nanostructures and metamaterials. Those approaches, however, offer qualitatively different strategies for tailoring light-matter interactions and are based on either high quality factor modes shaping, near field control, or both. Remarkably, rigorous quantum mechanical description might address those processes in a different fashion. While traditional cavity quantum electrodynamics tools are commonly based on mode decomposition approach, few challenges rise once dispersive and lossy nanostructures, such as noble metals (plasmonic) antennas or metamaterials, are involved. The primary objective of this review is to introduce key methods and techniques while aiming to obtain comprehensive quantum mechanical description of spontaneous, stimulated and higher order emission and interaction processes, tailored by nanostructured material environment. The main challenge and the complexity here are set by the level of rigorousity, up to which materials should be treated. While relatively big nanostructured features (10 nm and larger) could be addressed by applying fluctuation–dissipation theorem and corresponding Green functions' analysis, smaller objects will require individual approach. Effects of material granularity, spatial dispersion, tunneling over small gaps, material memory and others will be reviewed. Quantum phenomena, inspired and tailored by nanostructured environment, plays a key role in development of quantum information devices and related technologies. Rigorous analysis is required for both examination of experimental observations and prediction of new effects.
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.
Attempting to implement quantum information related applications utilizing atoms and photons, as they naturally form quantum systems supporting superposition states, hybrid quantum plasmonic systems emerged in the past as a platform to study and engineer light-matter interaction. This platform combines the unrivaled electromagnetic field localization of surface plasmon polaritons, boosting the light-matter coupling rate, with the tremendous integration potential of truly nanoscale structures, and both the significant emission rates of nanoantennas and photonic transmission velocities. In this work, a classical description of surface plasmon polaritons is combined with a light-matter interaction model based on a cavity quantum electrodynamical formalism. The resulting composite semi-classical method, introduced and described in this thesis, provides efficient and versatile means to simulate the dynamical behavior of radiative atomic transitions coupled to plasmonic cavity modes in the weak incoherent coupling regime. Both the emission into the far field and various dissipation mechanisms are included by expanding the model to an open quantum system. The variety of light-matter interaction applications that can be modeled with the outlined method is indicated by the four different exemplary scenarios detailed in the application chapter of this thesis. The classical description of localized surface plasmon polaritons is benchmarked by reproducing the experimental measurements of the molecular fluorescence manipulation through optical nanoantennas in a collaborative effort with experimental partners. Furthermore, in the weak light-matter coupling regime, the potential of achieving a higher nanoantenna functionality and simultaneously realizing more elaborate quantum dynamics is revealed by the three remaining applications. Each pivotally involving a bimodal nanoantenna and demonstrating different quantum optical phenomena, the implementation of cavity radiation mode conversion, non-classical cavity emission statistics, and non-classical cavity emission properties is shown and described in the application chapter.
The unprecedented pace of evolution in nanoscale architectures for cavity quantum electrodynamics (cQED) has posed crucial challenges for theory, where the quantum dynamics arising from the non-perturbative dressing of matter by cavity electric and magnetic fields as well as the fundamentally non-Hermitian character of the system are to be treated without significant approximation. The lossy electromagnetic resonances of photonic, plasmonic, or magnonic nanostructures are described as quasinormal modes (QNMs), whose properties and interactions with quantum emitters and spin qubits are central to the understanding of dissipative nano-optics and magnetodielectric cQED. Despite recent advancements toward a fully quantum framework for QNMs, a general and universally accepted approach to QNM quantization for arbitrary linear media remains elusive. In this work, we introduce a unified theoretical framework, based on macroscopic QED and complex coordinate transformations, which achieves QNM quantization for a wide class of spatially inhomogeneous, dissipative and dispersive, linear, magnetodielectric resonators. The complex coordinate transformations equivalently convert the radiative losses into non-radiative material dissipation, and via a suitable transformation that reflects all the losses of the resonator, we define creation and annihilation operators that allow the construction of modal Fock states for the joint excitations of field-dressed matter. By directly addressing the intricacies of modal loss in a fully quantum theory of magnetodielectric cQED, our approach enables the exploration of modern, quantum nano-optical experiments utilizing dielectric, plasmonic, magnetic, or hybrid cQED architectures and paves the way toward a rigorous assessment of room-temperature, quantum nanophotonic technologies without recourse to ad hoc quantization schemes.
Abstract Single-photon source in micro- or nanoscale is the basic building block of on-chip quantum information and scalable quantum network. Enhanced spontaneous emission based on cavity quantum electrodynamics (CQED) is one of the key principles of realizing single-photon sources fabricated by micro- or nanophotonic cavities. Here we mainly review the spontaneous emission of single emitters in micro- or nanostructures, such as whispering gallery microcavities, photonic crystals, plasmon nanostructures, metamaterials, and their hybrids. The researches have enriched light-matter interaction as well as made great influence in single-photon source, photonic circuit, and on-chip quantum information.
Summary form only given. In the pioneering work of Purcell, the possibility to control spontaneous emission lifetimes of quantum emitters by tailoring their electromagnetic surroundings was widely investigated and verified in various types of cavities or band-gap environments. This includes semiconductor microstructures, photonic crystals, and plasmonic nanoparticles. Due to the extraordinary ability of plasmonic nanostructures to confine light into subwavelength spatial domains, steps beyond the paradigmatic electric dipole approximation in the theoretical description of this process may be necessary. In this contribution, we focus on the case of multiple in general nonidentical two-level emitters, sharing the same electromagnetic surroundings, whose local density of states could be tailored by a neighbouring nanostructure. In this case, the surroundings may serve as a long-distance emitter-emitter interaction carrier, or it may trigger collective emission processes, in analogy to Dicke superradiance. We describe these phenomena taking into account the electric dipole, magnetic dipole and electric quadrupole components of light-matter interaction Hamiltonian.
Quantum light-matter interactions, described by the theory of quantum electrodynamics (QED), have motivated numerous scientific discoveries and technological developments over the past few decades. Considerable effort has been made to develop different QED platforms, e.g., free space, waveguides, cavities, and photonic crystals, for engineering quantum light-matter interactions. This thesis explores a new frontier, deep microscopic QED, which leverages the deep microscopic response of materials to reveal new topological, quantum, and thermal photonic phenomena with applications to quantum sensing and information processing. In the first part of this thesis, we investigate unique topological photonic effects arising in the deep microscopic QED regime. Previous efforts focused on topological photonic phases and edge states arising from artificial spatial structures of materials (e.g., photonic crystals or metamaterials). One fundamental question is whether topological photonic states can also arise from the intrinsic response of many-body systems and do not rely on materials' macroscopic structures. Here, we first discuss a new topological electromagnetic phase - ‘optical N-phase’ arising in two-dimensional (2D) viscous hydrodynamic electrons in graphene, which originates from the microscopic response of 2D materials and does not rely on materials' macroscopic structures. We then introduce the associated edge states, optical N-plasmons, which are topologically protected ultra-subwavelength edge magneto-plasmons. We further show how these topological plasmons can be harnessed to design chiral radio-frequency nonreciprocal circuit components, topological hydrodynamic circulators, that interface quantum and classical hardware.In the second part of this thesis, we focus on collective atom-photon interactions in the deep microscopic QED regime. In atom interactions with photonic environments, there exist two non-unitary processes -- pure dephasing and spontaneous emission. Despite considerable interest in collective effects in spontaneous emission since the 1950s, one long-standing problem is whether collective effects in pure dephasing can arise in atom-photon interactions. This question is particularly important in the quantum information era since pure dephasing is the main obstacle in current quantum information technologies. Here, we first introduce a new collective quantum phenomenon, ‘nanophotonic superdephasing,’ occurring in atom/spin ensembles in nanoscale photonic environments. This nanophotonic superdephasing phenomenon originates from low-frequency photonic environment correlations, and leads to collectively accelerated disentanglement without photon emission, in stark contrast to conventional collective spontaneous emission/superradiance effects. We further reveal the effects of nanophotonic environment mediated correlated dynamics on quantum computing and sensing. We demonstrate that correlations of nanoscale EM environments in spin qubit quantum computing devices can induce correlated errors and limit quantum gate fidelity. Meanwhile, based on nanophotonic collective dephasing, we also propose a multiqubit quantum sensing protocol that exploits spatially correlated noise near materials to enable order parameter symmetry characterization of materials beyond single-qubit methods.In the final part, we explore thermal photonic phenomena in the deep microscopic regime. Conventional techniques in engineering near-field radiative heat transfer typically rely on phonons, plasmons, and electromagnetic modes in structured materials. Here, we reveal a new approach to enhance near-field thermal radiation: leveraging intrinsic quantum coherence in superconducting materials. We reveal the quantum fingerprint of superconductivity in thermal photonics, ‘superconducting coherence peak’ in near-field thermal radiation, which originates from quantum coherence of Bogoliubov quasiparticles, with potential applications in thermal engineering in superconducting circuits.Overall, the thesis establishes a deep microscopic QED platform for new quantum, topological, and thermal photonic phenomena in many-body systems, with applications in quantum sensors and devices.