Coherent effects in quantum dot-metallic nanoparticle systems: plasmonic induction of Rabi oscillation and ultra-high fi
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Coherent effects in quantum dot-metallic nanoparticle systems: plasmonic induction of Rabi oscillation and ultra-high field enhancement S. M. Sadeghi1,2 1 Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899, USA 2 Nano and Micro Device Center, University of Alabama in Huntsville, Huntsville, AL 35899, USA ABSTRACT We theoretically show when single hybrid systems consisting of a metallic nanoparticle and a semiconductor quantum dot interact with a coherent light source (a laser field), quantum coherence in the quantum dot can dramatically influence the plasmonic field of the metallic nanoparticle. As a result, the quantum dot can self-renormalize the plasmonic field that it experiences. Using this we show when the applied laser field has a step-like amplitude rise, the effective field experienced by the quantum dot can exhibit strong oscillations with significantly high amplitudes for a short period of time. Our results also reveal the correlation between this effect and the Rabi flopping induced by plasmonic effects when a quantum dot is in the vicinity of a metallic nanoparticle. These results suggest that in a quantum dot-metallic nanoparticle system quantum coherence not only can change the magnitude of the field that the quantum dot experiences, but also, compared to the applied field, it can significantly increase the rate of its time variations. The results suggest that quantum dot-metallic nanoparticle systems can be appealing host for investigation of quantum plasmonic effects and photonic-plasmonic devices. INTRODUCTION Field enhancement caused by localized surface-plasmon resonances (LSPR) in metallic nanoparticles (MNPs) has been used for diverse applications, ranging from fundamental research for controlling the optics of semiconductor quantum dots (QDs) to the development of chemical and biological sensors [1,2]. In many of the existing literature plasmonic enhancement or suppression of the emission of a QD in presence of a MNP has been considered the prime property of the MNP, their center-to-center separation, and the dielectric constant of the environment [1,3,4]. In some recent reports, however, it has been shown this can only be valid when the effects of the coherence of the exciting light source can be ignored [6]. This happens, for example, when the QD-MNP system interacts with an incoherent light source or with a laser field under the conditions where the effects of its coherence are lost. When these effects are included the situation changes significantly. The main reason for this is that when a laser field interacts with a QD-MNP system, the quantum coherence generated in the QD can normalize the plasmonic field of the MNP significantly [7-11]. This in turn has opened up new opportunities for controlling near fields of MNPs [7-9], plasmonic quantum optics [10,11], and device applications [12-14]. In this contribution we investigate dynamics of coherent effects in QD-MNP systems, demonstrating how the field self-normalization of QDs can expand the horizon of the pla
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