Fundamental Limits for Light Absorption and Scattering Induced by Cooperative Electromagnetic Coupling

Absorption and scattering of electromagnetic waves by dielectric media are of fundamental importance in many branches of physics. In this Letter we analytically derived the ultimate upper limits for the absorbed and scattered powers by any system of optical resonators in mutual interaction. We show that these bounds depend only on the geometric configuration given an incident field. We give the conditions to fullfill to reach these limits paving so a way for a rational design of optimal metamaterials

Proposal for compact solid-state III-V single-plasmon sources

We propose a compact single-plasmon source operating at near-infrared wavelengths on an integrated III-V semiconductor platform, with a thin ridge waveguide serving as the plasmon channel. By attaching an ultra-small cavity to the channel, it is shown that both the plasmon generation efficiency ({\beta}) and the spontaneous-decay rate into the channel can be significantly enhanced. An analytical model derived with the Lorentz reciprocity theorem captures the main physics involved in the design of the source and yields results in good agreement with fully-vectorial simulations of the device. At resonance, it is predicted that the ultra-small cavity increases the {\beta}-factor by 70% and boosts the spontaneous decay rate by a factor 20. The proposed design could pave the way towards integrated and scalable plasmonic quantum networks. Comparison of the present design with other fully-dielectric competing approaches is addressed.Comment: 8 pages, 4 figure

A surface-scattering model satisfying energy conservation and reciprocity

In order for surface scattering models to be accurate they must necessarily satisfy energy conservation and reciprocity principles. Roughness scattering models based on Kirchoff's approximation or perturbation theory do not satisfy these criteria in all frequency ranges. Here we present a surface scattering model based on analysis of scattering from a layer of particles on top of a substrate in the dipole approximation which satisfies both energy conservation and reciprocity and is thus accurate in all frequency ranges. The model takes into account the absorption in the substrate induced by the particles but does not take into account the near-field interactions between the particles.Comment: 15 pages, 10 figure

RETICOLO software for grating analysis

RETICOLO implements the rigorous coupled wave analysis (RCWA) for 1D (classical and conical diffraction) and 2D crossed gratings. It operates under a MATLAB environment and incorporates an efficient and accurate toolbox for computing Bloch modes and visualizing the electromagnetic field in the grating region. As a spin-off, the Version V9 launched in 2021 includes a toolbox for the analysis of stacks of arbitrarily anisotropic multilayered thin-films

Polaritonic modes in a dense cloud of atoms

We analyze resonant light scattering by an atomic cloud in a regime where near-field interactions between scatterers cannot be neglected. We first use a microscopic approach and calculate numerically the eigenmodes of the cloud for many different realizations. It is found that there always exists a small number of polaritonic modes that are spatially coherent and superradiant. We show that scattering is always dominated by these modes. We then use a macroscopic approach by introducing an effective permittivity so that the atomic cloud is equivalent to a dielectric particle. We show that there is a one-to-one correspondence between the microscopic polaritonic modes and the modes of a homogeneous particle with an effective permittivity

Bound states in the continuum in symmetric and asymmetric photonic crystal slabs

We develop a semi-analytical model to describe bound states in the continuum (BICs) in photonic crystal slabs. We model leaky modes supported by photonic crystal slabs as a transverse Fabry-Perot resonance composed of a few propagative Bloch waves bouncing back and forth vertically inside the slab. This multimode Fabry-Perot model accurately predicts the existence of BICs and their positions in the parameter space. We show that, regardless of the slab thickness, BICs cannot exist below a cut-off frequency, which is related to the existence of the second-order Bloch wave in the photonic crystal. Thanks to the semi-analyticity of the model, we investigate the dynamics of BICs with the slab thickness in symmetric and asymmetric photonic crystal slabs. We evidence that the symmetry-protected BICs that exist in symmetric structures at the {\Gamma}-point of the dispersion diagram can still exist when the horizontal mirror symmetry is broken, but only for particular values of the slab thickness

Solid-state single photon sources: the nanowire antenna

International audienceWe design several single-photon-sources based on the emission of a quantum dot embedded in a semiconductor (GaAs) nanowire. Through various taper designs, we engineer the nanowire ends to realize efficient metallic-dielectric mirrors and to reduce the divergence of the far-field radiation diagram. Using fully-vectorial calculations and a comprehensive Fabry-Perot model, we show that various realistic nanowire geometries may act as nanoantennas (volume of ≈0.05 λ3) that assist funnelling the emitted photons into a single monomode channel. Typically, very high extraction efficiencies above 90% are predicted for a collection optics with a numerical aperture NA=0.85. In addition, since no frequency-selective effect is used in our design, this large efficiency is achieved over a remarkably broad spectral range, 70 nm at λ=950 nm

Non-Local Control of Single Surface Plasmon

Quantum entanglement is a stunning consequence of the superposition principle. This universal property of quantum systems has been intensively explored with photons, atoms, ions and electrons. Collective excitations such as surface plasmons exhibit quantum behaviors. For the first time, we report an experimental evidence of non-local control of single plasmon interferences through entanglement of a single plasmon with a single photon. We achieved photon-plasmon entanglement by converting one photon of an entangled photon pair into a surface plasmon. The plasmon is tested onto a plasmonic platform in a Mach-Zehnder interferometer. A projective measurement on the polarization of the photon allows the non-local control of the interference state of the plasmon. Entanglement between particles of various natures paves the way to the design of hybrid systems in quantum information networks.Comment: 6 pages, 3 figure