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.

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>

Size-dependent emission of a dipole coupled to a metal nanoparticle

MRS Advances ◽  
2020 ◽  
Vol 5 (62) ◽  
pp. 3315-3325
Author(s):  
Viktoriia Savchuk ◽  
Arthur R. Knize ◽  
Pavlo Pinchuk ◽  
Anatoliy O. Pinchuk
Keyword(s):  
Numerical Analysis ◽  
Quantum Yield ◽  
Electric Dipole ◽  
Incident Radiation ◽  
Metal Nanoparticle ◽  
Plasmonic Nanoparticle ◽  
Size Dependent ◽  
Emission Enhancement ◽  
Electric Dipoles

AbstractWe present a systematic numerical analysis of the quantum yield of an electric dipole coupled to a plasmonic nanoparticle. We observe that the yield is highly dependent on the distance between the electric dipole and the nanoparticle, the size and permittivity of the nanoparticle, and the wavelength of the incident radiation. Our results indicate that enhancement of the quantum yield is only possible for electric dipoles coupled to a nanoparticle with a radius of 20 nm or larger. As the size of the nanoparticle is increased, emission enhancement occurs at wavelengths dependent on the coupling distance.

scholarly journals Effects of gap thickness and emitter location on the photoluminescence enhancement of monolayer MoS2 in a plasmonic nanoparticle-film coupled system

Nanophotonics ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 2097-2105
Author(s):  
Xiaozhuo Qi ◽  
Tsz Wing Lo ◽  
Di Liu ◽  
Lantian Feng ◽  
Yang Chen ◽  
...  
Keyword(s):  
Near Field ◽  
Central Area ◽  
Field Enhancement ◽  
Coupled System ◽  
Film Structure ◽  
Plasmonic Nanoparticle ◽  
Emitter Location ◽  
Radiation Properties ◽  
Radiation Enhancement ◽  
Quantum Emitters

AbstractPlasmonic nanocavities comprised of metal film-coupled nanoparticles have emerged as a versatile nanophotonic platform benefiting from their ultrasmall mode volume and large Purcell factors. In the weak-coupling regime, the particle-film gap thickness affects the photoluminescence (PL) of quantum emitters sandwiched therein. Here, we investigated the Purcell effect-enhanced PL of monolayer MoS2 inserted in the gap of a gold nanoparticle (AuNP)–alumina (Al2O3)–gold film (Au Film) structure. Under confocal illumination by a 532 nm CW laser, we observed a 7-fold PL peak intensity enhancement for the cavity-sandwiched MoS2 at an optimal Al2O3 thickness of 5 nm, corresponding to a local PL enhancement of ∼350 by normalizing the actual illumination area to the cavity’s effective near-field enhancement area. Full-wave simulations reveal a counterintuitive fact that radiation enhancement comes from the non-central area of the cavity rather than the cavity center. By scanning an electric dipole across the nanocavity, we obtained an average radiation enhancement factor of about 65 for an Al2O3 spacer thickness of 4 nm, agreeing well with the experimental thickness and indicating further PL enhancement optimization. Our results indicate the importance of configuration optimization, emitter location and excitation condition when using such plasmonic nanocavities to modulate the radiation properties of quantum emitters.

scholarly journals Gauge invariance beyond the electric dipole approximation

2018 ◽  
Vol 98 (6) ◽  
Author(s):  
Ryoji Anzaki ◽  
Yasushi Shinohara ◽  
Takeshi Sato ◽  
Kenichi L. Ishikawa
Keyword(s):  
Electric Dipole ◽  
Gauge Invariance ◽  
Dipole Approximation

scholarly journals Importance of higher-order multipole transitions on chiral nearfield interactions

Nanophotonics ◽  
2019 ◽  
Vol 8 (5) ◽  
pp. 941-948 ◽  
Author(s):  
Jungho Mun ◽  
Junsuk Rho
Keyword(s):  
Dipole Approximation ◽  
Higher Order ◽  
Plasmonic Nanostructures ◽  
Chiral Molecules ◽  
Theoretical Frameworks ◽  
Full Field ◽  
3 Dimensional ◽  
Optical Chirality ◽  
T Matrix ◽  
Molecular Signals

AbstractSurface-enhanced circular dichroism (SECD) of chiral molecules adsorbed on plasmonic nanostructures can substantially enhance chiroptical molecular signals by several orders, which is otherwise very weak to be directly measured. Several mechanisms were proposed to explain this extreme enhancement, but the exact mechanism is still controversial. We investigate strong higher-order multipole contribution to SECD near plasmonic nanostructures using the superposition T-matrix method and discuss how 3-dimensional full-field simulations implementing a homogeneous chiral medium have succeeded in the reconstruction of the extreme enhancement. We also discuss how theoretical studies modeling chiral molecules based on dipole approximation have failed to reconstruct the extreme enhancement and show that SECD enhancement of such chiral dipoles is directly governed by optical chirality enhancement. In addition, strong multipolar transitions in subwavelength chiral plasmonic nanoparticles are discussed based on the T-matrix. This work reviews theoretical frameworks describing chiral molecules, demonstrates significant contribution of a multipolar transition on the extreme SECD enhancement near plasmonic nanostructures, and emphasizes the importance of a multipolar transition in chiral nearfield interaction.

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