scholarly journals Enhancement of and interference among higher order multipole transitions in molecules near a plasmonic nanoantenna

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Evgenia Rusak ◽  
Jakob Straubel ◽  
Piotr Gładysz ◽  
Mirko Göddel ◽  
Andrzej Kędziorski ◽  
...  
Keyword(s):  
Spontaneous Emission ◽  
Electric Dipole ◽  
Electric Quadrupole ◽  
Coherence Time ◽  
Dipole Approximation ◽  
Higher Order ◽  
Destructive Interference ◽  
Interference Effects ◽  
Matter Coupling ◽  
Molecular Transition

AbstractSpontaneous emission of quantum emitters can be modified by their optical environment, such as a resonant nanoantenna. This impact is usually evaluated under assumption that each molecular transition is dominated only by one multipolar channel, commonly the electric dipole. In this article, we go beyond the electric dipole approximation and take light-matter coupling through higher-order multipoles into account. We investigate a strong enhancement of the magnetic dipole and electric quadrupole emission channels of a molecule adjacent to a plasmonic nanoantenna. Additionally, we introduce a framework to study interference effects between various transition channels in molecules by rigorous quantum-chemical calculations of their multipolar moments and a consecutive investigation of the transition rate upon coupling to a nanoantenna. We predict interference effects between these transition channels, which allow in principle for a full suppression of radiation by exploiting destructive interference, waiving limitations imposed on the emitter’s coherence time by spontaneous emission.

A High-Resolution Linelist for Molecular Oxygen

2020 ◽  
Author(s):  
Wilfrid Somogyi ◽  
Sergey Yurchenko
Keyword(s):  
High Resolution ◽  
Molecular Oxygen ◽  
Electric Dipole ◽  
Electric Quadrupole ◽  
Dipole Approximation ◽  
Higher Order ◽  
Computational Techniques ◽  
Absorption Bands ◽  
Path Lengths ◽  
Homonuclear Diatomic Molecules

<p>Molecular oxygen (O<sub>2</sub>) is of particular interest in exoplanetary observations not least of all as an important biosignature on habitable planets. The atmospheric absorption bands are well studied, but a complete and accurate, high-resolution linelist is yet to be produced. Owing to their symmetry, the commonly employed electric dipole approximation is not valid for homonuclear diatomic molecules, and their rovibrational spectra are instead dominated by higher order transitions moments. These higher-order moments, such as the electric quadrupole and magnetic dipole, give rise to transition linestrengths that are orders of magnitude weaker than typical electric dipole transitions. Although such transitions are observable for atmospheric path lengths, their weak nature makes laboratory measurements especially challenging. In this work we develop and apply ab initio computational techniques to produce an accurate electric quadrupole spectrum of molecular oxygen presented for use in atmospheric retrievals across a range of temperatures, and made available through the ExoMol database.</p>

scholarly journals Interaction and Entanglement of a Pair of Quantum Emitters near a Nanoparticle: Analysis beyond Electric-Dipole Approximation

Entropy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 135 ◽  
Author(s):  
Miriam Kosik ◽  
Karolina Słowik
Keyword(s):  
Electric Dipole ◽  
Dipole Approximation ◽  
Higher Order ◽  
Collective Effects ◽  
Quantization Scheme ◽  
Multipole Interaction ◽  
Plasmonic Nanoparticle ◽  
Collective Response ◽  
Markovian Limit ◽  
Quantum Emitters

In this paper, we study the collective effects which appear as a pair of quantum emitters is positioned in close vicinity to a plasmonic nanoparticle. These effects include multipole–multipole interaction and collective decay, the strengths and rates of which are modified by the presence of the nanoparticle. As a result, entanglement is generated between the quantum emitters, which survives in the stationary state. To evaluate these effects, we exploit the Green’s tensor-based quantization scheme in the Markovian limit, taking into account the corrections from light–matter coupling channels higher than the electric dipole. We find these higher-order channels to significantly influence the collective rates and degree of entanglement, and in particular, to qualitatively influence their spatial profiles. Our findings indicate that, apart from quantitatively modifying the results, the higher-order interaction channels may introduce asymmetry into the spatial distribution of the collective response.

Light propagation in cubic and other anisotropic crystals

1990 ◽  
Vol 430 (1880) ◽  
pp. 593-614 ◽  
Keyword(s):  
Optical Activity ◽  
Electric Dipole ◽  
Light Propagation ◽  
Light Wave ◽  
Electric Quadrupole ◽  
Dipole Approximation ◽  
Multipole Moments ◽  
Magnetic Dipoles ◽  
Cubic Crystals

A consistent multipole theory is presented to describe light propagation in non-absorbing non-magnetic crystals. Although valid for the 32 crystal classes, the theory is applied here to all except the five members of the triclinic and monoclinic systems. To account for the birefringence that has been observed in certain cubic crystals and also for the predicted Jones birefringence, the theory has to allow for electric octopoles and magnetic quadrupoles induced by the light wave. At the earlier stage of electric quadrupoles and magnetic dipoles, it is able to describe optical activity in crystals. An expression for this is derived which, when electric quadrupole contributions are omitted, yields the familiar Nye result. As a criterion for the correct inclusion in the theory of all relevant induced multipole moments, tensor expressions for observables are shown to be independent of the choice of origin. Finally, the concepts of O-ray and E-ray are found to break down beyond the electric dipole approximation and alternatives are proposed.

Full Optical Rotation Tensor at CCSD Level in the Modified Velocity Gauge

2020 ◽  
Author(s):  
Kaihua Zhang ◽  
Ty Balduf ◽  
Marco Caricato
Keyword(s):  
Electric Dipole ◽  
Optical Rotation ◽  
Electric Quadrupole ◽  
Polarizability Tensor ◽  
Dipole Polarizability ◽  
Difficult Case ◽  
Computationally Efficient ◽  
Rotation Tensor ◽  
Approximate Methods ◽  
Velocity Gauge

<div> <div> <p> </p><div> <div> <div> <p>This work presents the first simulations of the full optical rotation (OR) tensor at coupled cluster with single and double excitations (CCSD) level in the modified velocity gauge (MVG) formalism. The CCSD-MVG OR tensor is origin independent, and each tensor element can in principle be related directly to experimental measurements on oriented systems. We compare the CCSD results with those from two density functionals, B3LYP and CAM-B3LYP, on a test set of 22 chiral molecules. The results show that the functionals consistently overestimate the CCSD results for the individual tensor components and for the trace (which is related to the isotropic OR), by 10-20% with CAM-B3LYP and 20-30% with B3LYP. The data show that the contribution of the electric dipole-magnetic dipole polarizability tensor to the OR tensor is on average twice as large as that of the electric dipole-electric quadrupole polarizability tensor. The difficult case of (1S,4S)-(–)-norbornenone also reveals that the evaluation of the former polarizability tensor is more sensitive than the latter. We attribute the better agreement of CAM-B3LYP with CCSD to the ability of this functional to better reproduce electron delocalization compared with B3LYP, consistently with previous reports on isotropic OR. The CCSD-MVG approach allows the computation of reference data of the full OR tensor, which may be used to test more computationally efficient approximate methods that can be employed to study realistic models of optically active materials. </p> </div> </div> </div> </div> </div>

scholarly journals Suppression of scattering for small dielectric particles: anapole mode and invisibility

2017 ◽  
Vol 375 (2090) ◽  
pp. 20160069 ◽  
Author(s):  
Boris Luk'yanchuk ◽  
Ramón Paniagua-Domínguez ◽  
Arseniy I. Kuznetsov ◽  
Andrey E. Miroshnichenko ◽  
Yuri S. Kivshar
Keyword(s):  
Refractive Index ◽  
Electric Dipole ◽  
Fano Resonance ◽  
Optical Materials ◽  
High Refractive Index ◽  
Destructive Interference ◽  
Total Scattering ◽  
Dipole Radiation ◽  
New Horizons ◽  
Dielectric Particles

We reveal that an isotropic, homogeneous, subwavelength particle with high refractive index can produce ultra-small total scattering. This effect, which follows from the inhibition of the electric dipole radiation, can be identified as a Fano resonance in the scattering efficiency and is associated with the excitation of an anapole mode in the particle. This anapole mode is non-radiative and emerges from the destructive interference of electric and toroidal dipoles. The invisibility effect could be useful for the design of highly transparent optical materials. This article is part of the themed issue ‘New horizons for nanophotonics’.

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