The phenomenon of extraordinary light transmission through metallic films perforated by nanohole arrays at optical frequencies was first observed a decade ago and initiated important further ...experimental and theoretical work. In view of potential applications of such structures--for example, subwavelength optics, optoelectronics devices, and chemical sensing--it is important to understand the underlying physical processes in detail. Here we derive a microscopic theory of the transmission through subwavelength hole arrays, by considering the elementary processes associated with scattering of surface-plasmon-polariton (SPP) modes by individual one-dimensional chains of subwavelength holes. Using a SPP coupled-mode model that coherently gathers these elementary processes, we derive analytical expressions for all the transmission spectrum characteristics--such as the resonance wavelength, the peak transmission and the anti-resonance. Further comparisons of the model predictions with fully vectorial computational results allow us quantitatively to check the model accuracy and to discuss the respective impacts of SPP modes and of other electromagnetic fields on producing the extraordinary transmission of light. The model greatly expands our understanding of the phenomenon and may affect further engineering of nanoplasmonic devices.
We derive a closed-form expression that accurately predicts the peak frequency shift and broadening induced by tiny perturbations of plasmonic nanoresonators without critically relying on repeated ...electrodynamic simulations of the spectral response of nanoresonator for various locations, sizes, or shapes of the perturbing objects. In comparison with other approaches of the same kind, the force of the present approach is that the derivation is supported by a mathematical formalism based on a rigorous normalization of the resonance modes of nanoresonators consisting of lossy and dispersive materials. Accordingly, accurate predictions are obtained for a large range of nanoparticle shapes and sizes used in various plasmonic nanosensors even beyond the quasistatic limit. The expression gives quantitative insight and, combined with an open-source code, provides accurate and fast predictions that are ideally suited for preliminary designs or for interpretation of experimental data. It is also valid for photonic resonators with large mode volumes.
The macroscopic electromagnetic boundary conditions, which have been established for over a century
, are essential for the understanding of photonics at macroscopic length scales. Even ...state-of-the-art nanoplasmonic studies
, exemplars of extremely interface-localized fields, rely on their validity. This classical description, however, neglects the intrinsic electronic length scales (of the order of ångström) associated with interfaces, leading to considerable discrepancies between classical predictions and experimental observations in systems with deeply nanoscale feature sizes, which are typically evident below about 10 to 20 nanometres
. The onset of these discrepancies has a mesoscopic character: it lies between the granular microscopic (electronic-scale) and continuous macroscopic (wavelength-scale) domains. Existing top-down phenomenological approaches deal only with individual aspects of these omissions, such as nonlocality
and local-response spill-out
. Alternatively, bottom-up first-principles approaches-for example, time-dependent density functional theory
-are severely constrained by computational demands and thus become impractical for multiscale problems. Consequently, a general and unified framework for nanoscale electromagnetism remains absent. Here we introduce and experimentally demonstrate such a framework-amenable to both analytics and numerics, and applicable to multiscale problems-that reintroduces the electronic length scale via surface-response functions known as Feibelman d parameters
. We establish an experimental procedure to measure these complex dispersive surface-response functions, using quasi-normal-mode perturbation theory and observations of pronounced nonclassical effects. We observe nonclassical spectral shifts in excess of 30 per cent and the breakdown of Kreibig-like broadening in a quintessential multiscale architecture: film-coupled nanoresonators, with feature sizes comparable to both the wavelength and the electronic length scale. Our results provide a general framework for modelling and understanding nanoscale (that is, all relevant length scales above about 1 nanometre) electromagnetic phenomena.
Light emitters or scatterers embedded in stratified media may couple energy to both free-space modes and guided modes of the stratified structure. For a comprehensive analysis, it is important to ...evaluate the angular intensity distribution of both the free-space modes and guided modes excited in such systems. In the present work, we propose an original method based on Lorentz reciprocity theorem to efficiently calculate the free-space and guided radiation diagrams with a high accuracy from the sole knowledge of the near-field around the emitters or scatterers. Compared to conventional near-to-far field transformation techniques, the proposal allows one to easily evaluate the guided-mode radiation diagrams, even if material dissipation is present in the stack, and thus to simultaneously track the coupling of light to all channels (i.e., free-space and guided ones). We also provide an open-source code that may be used with essentially any Maxwell’s equation solver. The numerical tool may help to engineer various devices, such as light-emitting diodes or nanoantennas, to achieve directional and efficient radiative spontaneous decays in free-space and guided optics.
The development of efficient solid-state sources of single photons is a major challenge in the context of quantum communication, optical quantum information processing and metrology. Such a source ...must enable the implementation of a stable, single-photon emitter, like a colour centre in diamond or a semiconductor quantum dot. Achieving a high extraction efficiency has long been recognized as a major issue, and both classical solutions and cavity quantum electrodynamics effects have been applied. We adopt a different approach, based on an InAs quantum dot embedded in a GaAs photonic nanowire with carefully tailored ends. Under optical pumping, we demonstrate a record source efficiency of 0.72, combined with pure single-photon emission. This non-resonant approach also provides broadband spontaneous emission control, thus offering appealing novel opportunities for the development of single-photon sources based on spectrally broad emitters, wavelength-tunable sources or efficient sources of entangled photon pairs.
Hybrid systems made of quantum emitters and plasmonic nanoresonators offer a unique platform to implement artificial atoms with completely novel optical responses that are not available otherwise. ...However, their theoretical analysis is difficult, and since many degrees of freedom have to be explored, engineering their optical properties remains challenging. Here, we propose a new formalism that removes most limitations encountered in previous analytical treatments and allows a flexible and efficient study of complex nanoresonators with arbitrary shapes in an almost fully analytically way. The formalism brings accurate closed-form expressions for the hybrid-system optical response and provides an intuitive description based on the coupling between the quantum emitters and the resonance modes of the nanoresonator. The ability to quickly predict light-scattering properties of hybrid systems paves the way to a deep exploration of their fascinating properties and may enable rapid optimization of quantum plasmonic metamaterials or quantum information devices.
We experimentally investigate the spontaneous emission (SE) rates of single InAs quantum dots embedded in GaAs photonic nanowires. For a diameter leading to the optimal confinement of the fundamental ...guided mode HE11, the coupling to HE11 dominates the SE process and an increase of the SE rate by a factor of 1.5 is achieved. When the diameter is decreased, the coupling to this mode vanishes rapidly, thus allowing the coupling to the other radiation modes to be probed. In these conditions, a SE inhibition factor of 16, equivalent to the one obtained in state-of-the-art photonic crystals, is measured. These results, which are supported by fully vectorial calculations, confirm the potential of photonic nanowires for a nearly perfect, broadband SE control.
We analyse the resonant mode structure and local density of states in high-Q hybrid plasmonic-photonic resonators composed of dielectric microdisks hybridized with pairs of plasmon antennas that are ...systematically swept in position through the cavity mode. On the one hand, this system is a classical realization of the cooperative resonant dipole-dipole interaction through a cavity mode, as is evident through predicted and measured resonance linewidths and shifts. At the same time, our work introduces the notion of 'phased array' antenna physics into plasmonic-photonic resonators. We predict that one may construct large local density of states (LDOS) enhancements exceeding those given by a single antenna, which are 'chiral' in the sense of correlating with the unidirectional injection of fluorescence into the cavity. We report an experiment probing the resonances of silicon nitride microdisks decorated with aluminium antenna dimers. Measurements directly confirm the predicted cooperative effects of the coupled dipole antennas as a function of the antenna spacing on the hybrid mode quality factors and resonance conditions.
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