Atti della Accademia Peloritana dei Pericolanti. Classe di Scienze Fisiche, Matematiche e Naturali/Atti della Accademia Peloritana dei Pericolanti, Classe di Scienze Fisiche, Matematiche e Naturali
LIGHT SCATTERING AND PHOTON STATISTICS OF QUANTUM EMITTERS COUPLED TO METALLIC NANOPARTICLES
Omar Di Stefano, A. Ridolfo, Rosalba Saija, Salvatore Savasta
ABSTRACT. We study theoretically the quantum optical properties of hybrid artificial molecules composed of an individual quantum emitter and a metallic nanoparticle. The coupling between the two systems can give rise to a Fano interference effect which strongly influences the quantum statistical properties of the scattered photons: a small frequency shift of the incident light field may cause changes in the intensity correlation function of the scattered field of orders of magnitude. The system opens a good perspective for applica-tions in active metamaterials and ultracompact single-photon devices. We also demonstrate with accurate scattering calculations that a system constituted by a single quantum emitter (a semiconductor quantum dot) placed in the gap between two metallic nanoparticles can display the vacuum Rabi splitting. 1.
ABSTRACT. We study theoretically the quantum optical properties of hybrid artificial molecules composed of an individual quantum emitter and a metallic nanoparticle. The coupling between the two systems can give rise to a Fano interference effect which strongly influences the quantum statistical properties of the scattered photons: a small frequency shift of the incident light field may cause changes in the intensity correlation function of the scattered field of orders of magnitude. The system opens a good perspective for applica-tions in active metamaterials and ultracompact single-photon devices. We also demonstrate with accurate scattering calculations that a system constituted by a single quantum emitter (a semiconductor quantum dot) placed in the gap between two metallic nanoparticles can display the vacuum Rabi splitting. 1.
We study theoretically the quantum optical properties of hybrid molecules composed of an individual quantum dot and a metallic nanoparticle. We calculate the resonance fluorescence of this composite system. Its incoherent part, arising from nonlinear quantum processes, is enhanced by more than 2 orders of magnitude as compared to that of the dot alone. The coupling between the two systems gives rise to a Fano interference effect which strongly influences the quantum statistical properties of the scattered photons: a small frequency shift of the incident light field may cause changes in the intensity correlation function of the scattered field of orders of magnitude. The system opens a good perspective for applications in active metamaterials and ultracompact single-photon devices.
We study theoretically the quantum optical properties of hybrid molecules composed of an individual quantum dot and a metallic nanoparticle. We calculate the resonance fluorescence of this hybrid system. Its incoherent part, the one arising from nonlinear quantum processes, results to be enhanced by more than two orders of magnitude as compared to that in the absence of the metallic nanoparticle. Scattering spectra at different excitation powers and nonperturbative calculations of intensity-field correlation functions show that this system can act as a nonlinear ultra-compact two-photon switch for incident photons, where the presence (or absence) of a single incident photon field is sufficient to allow (or prevent) the scattering of subsequent photons. We also find that a small frequency shift of the incident light field may cause changes in the intensity field correlation function of orders of magnitude.
The principle of complementarity refers to the ability of quantum entities to behave as particles or waves under different experimental conditions. I discuss a recently proposed device enabling the ultrafast all optical control of the wave‐particle duality of light. It is constituted by a three‐level quantum emitter strongly coupled to a microcavity and can be realized by exploiting a great variety of systems ranging from atomic physics and semiconductor quantum dots to intersubband polaritons and Cooper pair boxes. Control pulses with specific arrival times, performing which‐path and quantum‐eraser operations, are able to destroy and recover interference almost instantaneously. I will also discuss quantum coherence effects and more generally the optical properties of ultracompact (with dimensions below the diffraction limit) hybrid structures, composed of metallic nanoparticles and a single quantum dot. The coupling between a single quantum emitter and a metallic nanoparticle can give rise to a Fano interference effect which strongly influences the quantum statistical properties of the scattered photons.
Quantum engineering of photons is a key requirement for the development of quantum technology. Here, we put forward a scheme to investigate extensively quantum statistical characteristics of the photons and their engineering in a hybrid nanoparticle-emitter-cavity architecture through placing a nanoparticle (NP) and a quantum emitter (QE), called NP-QE molecule, into an optical cavity, where the coherent tripartite coupling emerges in the interactions among the NP, QE, and cavity. The photons are collected from the two different channels, i.e., the cavity emission and the NP-QE molecule scattering. Due to the composite nature of the tripartite dressed excitations of our fully coupled system and the destructive interference between different transition pathways for the two-photon excitation, the nontrivial quantum statistical properties, such as unconventional single-photon blockade and strong photon superbunching, can be achieved even within the bad cavity limit (without the need of the strong-coupling condition) when the NP-QE molecule is driven by an external laser not interacting the cavity mode. It is also revealed that the photon autocorrelation and cross-correlation properties are well modified by regulating the size-dependent system parameters, such as the NP-to-QE distance and the NP radius. The small-coupling strength required, the ease of parameter tuning, the relaxation of high-cavity quality factor, and the robustness to the dephasing rate in realistic scenarios all benefit the generation of single-photon sources, which has potential applications in quantum information and quantum communication.
Metal nanoparticles (MNPs) possess the intriguing property of enhancing and limiting the energy of light field to subwavelength scale, which have attracted extensive attention in physics, chemistry, and life sciences. Meanwhile, squeezing is a general concept in quantum optics and can be used to engineer matter interaction scenarios. Here we consider an artificial hybrid molecule consisting of an MNP interacting with a semiconductor quantum dot (QD), combining with a squeezed reservoir. Using experimentally realistic parameters for the MNP-QD architecture and fully quantized approach, we theoretically explore the optical properties of the hybrid molecule driven by an external applied laser field via probing the resonance fluorescence in the steady state. We show that in this way it is possible to engineer and control the peak-value magnitudes, widths, and shapes of the resonance fluorescence spectra under the influence of the squeezed vacuum field without the need for the strong-coupling condition between the MNP and QD. In particular, some interesting phenomena in rich spectral responses are attainable, including Fano-type resonance fluorescence, fluorescence quenching, fluorescence narrowing, and fluorescence enhancement. Our method can also be extended to other nanoscopic structures, such as a plasmonic nanoantenna coupled to an emitter. These unique line shapes obtained here may have potential applications in developing quantum plasmonic platforms and sensitive on-chip devices such as optical switches and sensors.
We investigate the quantum optical properties of strong light-matter interaction between a quantum emitter and a metallic nanoparticle beyond idealized structures with a smooth surface. Based on the local coupling strength and macroscopic Green's function, we derived an exact quantum optics approach to obtain the field enhancement and light-emission spectrum of a quantum emitter. Numerical simulations show that the surface roughness has a greater effect on the near-field than on the far-field, and slightly increases the vacuum Rabi splitting on average. Further, we verified that the near-field enhancement is mainly determined by the surface features of hot-spot area.