Thermal effects on the resonance fluorescence of doubly dressed artificial atoms

In this work, robustness of controlled density of optical states in doubly driven artificial atoms is studied under phonon dissipation. By using both perturbative and polaron approaches, we investigate the influence of carrier-phonon interactions on the emission properties of a two-level solid-state emitter, simultaneously coupled to two intense distinguishable lasers. Phonon decoherence effects on the emission spectra are found modest up to neon boiling temperatures ($\sim 30$ K), as compared with photon generation at the Fourier transform limit obtained in absence of lattice vibrations (zero temperature). These results show that optical switching and photonic modulation by means of double dressing, do not require ultra low temperatures for implementation, thus boosting its potential technological applications.Comment: Submitted versio

Tunneling Effects on Fine-Structure Splitting in Quantum Dot Molecules

We theoretically study the effects of bias-controlled interdot tunneling in vertically coupled quantum dots on the emission properties of spin excitons in various bias-controlled tunneling regimes. As a main result, for strongly coupled dots we predict substantial reduction of optical fine structure splitting without any drop in the optical oscillator strength. This special reduction diminishes the distinguibility of polarized decay paths in cascade emission processes suggesting the use of stacked quantum dot molecules as entangled photon-pair sources.Comment: 12 pages, 4 figures, submitted to a APS journa

Analytical obtention of eigen-energies for lens-shaped quantum dot with finite barriers

The bound states of a particle in a lens-shaped quantum dot with finite confinement potential are obtained in the envelope function approximation. The quantum dot has circular base with radius $a$ and maximum cap height $b$, and the effective mass of the particle is considered different inside and outside the dot. A 2D Fourier expansion is used in a semi-sphere domain with infinite walls which contains the geometry of the original potential. Electron energies for different values of lens deformation $b/a$, lens radius $a$ and barrier height $V_o$ are calculated. In the very high confinement potential limit, the results for the infinite barrier case are recovered.Comment: 5 pages, 3 figures, accepted for publication in The European Physical Journal

Influence of the confinement potential on the size-dependent optical response of metallic nanometric particles

In this paper, different confinement potential approaches are considered in the simulation of size effects on the optical response of silver spheres with radii at the few nanometer scale. By numerically obtaining dielectric functions from different sets of eigenenergies and eigenstates, we simulate the absorption spectrum and the field enhancement factor for nanoparticles of various sizes, within a quantum framework for both infinite and finite potentials. The simulations show significant dependence on the sphere radius of the dipolar surface plasmon resonance, as a direct consequence of energy discretization associated to the strong confinement experienced by conduction electrons in small nanospheres. Considerable reliance of the calculated optical features on the chosen wave functions and transition energies is evidenced, so that discrepancies in the plasmon resonance frequencies obtained with the three studied models reach up to above 30%. Our results are in agreement with reported measurements and shade light on the puzzling shift of the plasmon resonance in metallic nanospheres.The authors would like to thank financial backing. M.Z.H. acknowledges support from Colciencias through the Ph.D. studentship program no. 567, the Spanish Ministry of Economy and Competitiveness MINECO through project FIS2016-80174-P, as well as support from NIST Grant No. 70NANB15H32 of the US Department of Commerce. A.S.C. acknowledges support from the Department of Physics of the Universidad de Los Andes, and H.Y.R. acknowledges support from the Research Division of the Universidad Pedagógica y Tecnológica de Colombia (UPTC) under research grant SGI-2142.Peer reviewe

Quantum confinement effects on the near field enhancement in metallic nanoparticles

In this work, we study the strong confinement effects on the electromagnetic response of metallic nanoparticles. We calculate the field enhancement factor for nanospheres of various radii by using optical constants obtained from both classical and quantum approaches, and compare their size dependent features. To evaluate the scattered near field, we solve the electromagnetic wave equation within a finite element framework. When quantization of electronic states is considered for the input optical functions, a significant blue-shift in the resonance of the enhanced field is observed, in contrast to the case in which functions obtained classically are used. Furthermore, a noticeable underestimation of the field amplification is found in the calculation based on a classical dielectric function. Our results are in good agreement with available experimental reports and provide relevant information on the cross-over between classical and quantum regime, useful in potentiating nanoplasmonics applications.The authors acknowledge the Department of Physics of the Universidad de Los Andes, and the UPTC’s Research Division for financial support.Peer reviewe