Highly entangled photon pairs generated from the biexciton cascade transition in a quantum-dot–metal-nanoparticle hybrid system

Abstract

The entanglement between photon pairs generated from the biexciton cascade transition in a semiconductor quantum dot located in the vicinity of a metal nanoparticle is theoretically investigated. In the model scheme, the biexciton-exciton and exciton-ground state transitions are assumed to be coupled to two principal plasmon modes of orthogonal polarizations. For a broad spectral window, because the horizontal and vertical spectra are overlapped, the biexciton and exciton photons are degenerate in energy. This allows us to overcome the natural splitting between the intermediate exciton states. Moreover, the degree of entanglement depends on the geometrical parameters of the system. i.e., the radius of the metal nanoparticle and the distance between the quantum dot and the nanoparticle. The results reveal that such a hybrid system profoundly modifies the photon entanglement even in the absence of strong coupling between the emitter and the metal nanosphere.

Photon antibunching control in a quantum dot and metallic nanoparticle hybrid system with non-Markovian dynamics

“…Since the plasmonic modes are excited at optical frequencies whose energy scales are much higher than the thermal energy k B T , it is reasonable to assume that the system is at zero temperature [33,34]. Therefore, we can use the following correlation functions for the reservoir operators:…”

“…The interaction of an MNP with light leads to non-propagating excitations of the conduction electrons of the MNP; the quanta of these excitations are called localized surface plasmons (LSPs) [30]. The evanescent near-field associated to the LSPs increases the local density of states (LDOS) around the MNP dramatically [31][32][33][34][35][36]. When a QD, as an emitter, is located in the evanescent field of an MNP, the decay rate of the QD is affected through the LDOS and increases significantly [31][32][33]36].…”

“…Moreover, the antibunching behavior of the emitted photons can be controlled by the geometrical parameters of the system, namely, the quantum dot-metal nano particle separation distance, as well as the system's physical parameters including the detuning frequency of the quantum dot transitions with respect to the surface plasmon modes, and the Rabi frequency of the polarized driving field. Additionally, the studied system has the potential to be a highly controllable single-photon source.(LDOS) around the MNP dramatically [31][32][33][34][35][36]. When a QD, as an emitter, is located in the evanescent field of an MNP, the decay rate of the QD is affected through the LDOS and increases significantly [31][32][33]36].…”

“…(LDOS) around the MNP dramatically [31][32][33][34][35][36]. When a QD, as an emitter, is located in the evanescent field of an MNP, the decay rate of the QD is affected through the LDOS and increases significantly [31][32][33]36].…”

Mechanistic Understanding of Entanglement and Heralding in Cascade Emitters

“…This results in anticorrelation in the polarization of the emitted photons. [30][31][32][33] Figure 1: Schematic of radiative decay of the biexciton state |XX in a typical(asymmetric) QD with fine-structure splitting ∆ F SS . Here we assume the radiative decay of |XX generates a pair of vertically or horizontally colinearly polarized photons;…”