475 research outputs found
Theoretical treatment of the interaction between two-level atoms and periodic waveguides
Light transport in periodic waveguides coupled to a two-level atom is
investigated. By using optical Bloch equations and a photonic modal formalism,
we derive semi-analytical expressions for the scattering matrix of one atom
trapped in a periodic waveguide. The derivation is general, as the expressions
hold for any periodic photonic or plasmonic waveguides. It provides a basic
building block to study collective effects arising from photon-mediated
multi-atom interactions in periodic waveguides.Comment: 6 pages with 3 figure
Simple analytical expression for the peak-frequency shifts of plasmonic resonances for sensing
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. The force of the present approach,
in comparison with other approaches of the same kind, 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.Comment: 24 pages, 9 figures, journal pape
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
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
Quasinormal-mode modeling and design in nonlinear nano-optics
Based on quasinormal-mode theory, we propose a novel approach enabling a deep
analytical insight into the multi-parameter design and optimization of
nonlinear photonic structures at subwavelength scale. A key distinction of our
method from previous formulations relying on multipolar Mie-scattering
expansions is that it directly exploits the natural resonant modes of the
nanostructures, which provide the field enhancement to achieve significant
nonlinear efficiency. Thanks to closed-form expression for the nonlinear
overlap integral between the interacting modes, we illustrate the potential of
our method with a two-order-of-magnitude boost of second harmonic generation in
a semiconductor nanostructure, by engineering both the sign of at
subwavelength scale and the structure of the pump beam
Non-uniqueness of the Quasinormal Mode Expansion of Electromagnetic Lorentz Dispersive Materials
Any optical structure possesses resonance modes and its response to an
excitation can be decomposed onto the quasinormal and numerical modes of
discretized Maxwell's operator. In this paper, we consider a dielectric
permittivity that is a N-pole Lorentz function of the pulsation . We
propose a common formalism and obtain different formulas for the modal
expansion. The non-uniqueness of the excitation coeffcient is due to a choice
of the linearization of Maxwell's equation with respect to and of the
form of the source term. We make the link between the numerical discrete modal
expansion and analytical formulas that can be found in the literature. We
detail the formulation of dispersive Perfectly Matched Layers (PML) in order to
keep a linear eigenvalue problem. We also give an algorithm to regain an
orthogonal basis for degenerate modes. Numerical results validate the different
formulas and compare their accuracy.Comment: 11 figures, 21 page
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