We study theoretically four-wave parametric amplification arising from the nonlinear optical response of hybrid molecules composed of semiconductor quantum dots and metallic nanoparticles. It is shown that highly efficient four-wave parametric amplification can be achieved by adjusting the frequency and intensity of the pump field and the distance between the quantum dot and the metallic nanoparticle. Specifically, the induced probe-wave gain is tunable in a large range from 1 to 1.43 × 10⁵. This gain reaches its maximum at the position of three-photon resonance. Our findings hold great promise for developing four-wave parametric oscillators.
We study theoretically four-wave parametric amplification arising from the nonlinear optical response of hybrid molecules composed of semiconductor quantum dots and metallic nanoparticles. It is shown that highly efficient four-wave parametric amplification can be achieved by adjusting the frequency and intensity of the pump field and the distance between the quantum dot and the metallic nanoparticle. Specifically, the induced probe-wave gain is tunable in a large range from 1 to 1.43 × 10⁵. This gain reaches its maximum at the position of three-photon resonance. Our findings hold great promise for developing four-wave parametric oscillators.
We investigate theoretically four-wave mixing (FWM) response and optical bistability (OB) in a hybrid nanosystem composed of a metal nanoparticle (MNP) and a semiconductor quantum dot (SQD) coupled to a nanomechanical resonator (NR). It is shown that the FWM signal is enhanced by more than three orders of magnitude as compared to that of the system without exciton-phonon interaction, and the FWM signal can also be suppressed significantly and broadened due to the exciton-plasmon interaction. As the MNP couples strongly with the SQD, the bistable FWM response can be achieved by adjusting the SQD-MNP distance and the pumping intensity. For a given pumping constant and a fixed SQD-MNP distance, the enhanced exciton-phonon interaction can promote the occurrence of bistability. Our findings not only present a feasible way to detect the spacing between two nanoparticles, but also hold promise for developing quantum switches and nanoscale rulers.
In this study, the four-wave mixing (FWM) spectrum of a strongly pumped hybrid structure is theoretically examined. The hybrid structure consists of an asymmetric double semiconductor quantum dot (SQD) molecule and a spherical metal nanoparticle (MNP), which are coupled together via long-range Coulomb interaction. Having as a starting point the Hamiltonian of the system, in the dipole and the rotating-wave approximations, we derive a set of nonlinear density matrix equations, which are numerically solved, in the steady-state limit, and then the FWM coefficient is calculated within a range of values of the pump–probe field detuning. The spectral response of the FWM coefficient is investigated, for different values of the pump-field detuning, the electron-tunneling rate, and the energy gap between the upper states in the energy-level scheme of the double SQD molecule, while the interparticle distance between the two components of the structure is modified.
We study optical effects in a hybrid system composed of a semiconductor quantum dot and a spherical metal nanoparticle that interacts with a weak probe electromagnetic field. We use modified nonlinear density matrix equations for the description of the optical properties of the system and obtain a closed-form expression for the linear susceptibilities of the quantum dot, the metal nanoparticle, and the total system. We then investigate the dependence of the susceptibility on the interparticle distance as well as on the material parameters of the hybrid system. We find that the susceptibility of the quantum dot exhibits optical transparency for specific frequencies. In addition, we show that there is a range of frequencies of the applied field for which the susceptibility of the semiconductor quantum dot leads to gain. This suggests that in such a hybrid system quantum coherence can reverse the course of energy transfer, allowing flow of energy from the metallic nanoparticle to the quantum dot. We also explore the susceptibility of the metal nanoparticle and show that it is strongly influenced by the presence of the quantum dot.
The emergence of hybrid nanostructures has paved a novel path for the development of nanotechnology and next-generation quantum devices.In this study, we report a remarkable enhancement of nonlinear diffraction achieved within a hybrid artificial molecule consisting of a semiconductor quantum dot (SQD) and a metal nanoparticle (MNP).Our findings reveal that the optical nonlinear properties of the hybrid system can be substantially enhanced due to the plasmon resonance of MNP.Specifically, reducing the interparticle distance and the SQD's size while increasing the MNP's size leads to a significant enhancement in the nonlinear phase modulation of the hybrid system.Meanwhile, the absorption spectra exhibit a redshift accompanied by linewidth broadening under the SQD-MNP coupling interaction controlled by geometric parameters, indicating plasmon-exciton energy transfer.On this basis, it is validated that the enhanced nonlinear phase modulation greatly improves the self-imaging visibility and the signal-to-noise ratio, and extends the near-field pattern over more Talbot lengths.We also demonstrate that the far-field diffraction efficiency is tunable via the coupling interaction between the artificial molecule and external fields, which is determined by the geometric structure, photon detuning, and Rabi frequency.For instance, the first-order diffraction efficiency can be increased from 39.58% to 55% if the geometric parameters of the hybrid system satisfy the threshold in non-resonance conditions.Such plasmon-enhanced optical lattices show potential for applications in all-optical modulators and all-optical switches operating at few-photon levels, and may also afford a novel perspective for the design and development of nanophotonics circuits and topological photonic 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.
In the present work, we investigate the modified nonlinear pump-probe optical properties due to the excitonic–plasmonic interaction of a double semiconductor quantum dot (SQD) molecule coupled to a metal nanoparticle (MNP). More specifically, we study the absorption and the dispersion spectra of a weak electromagnetic field in a hybrid structure with two counterparts, a molecule of two coupled SQDs, and a spherical MNP driven by a field of high intensity. We solve the relevant density matrix equations, calculate the first-order optical susceptibility of the probe field in the strong pumping regime, and investigate the way in which the distance between the two counterparts modifies the optical response, for a variety of values of the physical constants of the system, including the pump-field detuning, the tunnelling rate, and the energy separation gap associated with the excited states of the coupled SQDs.