Quantum optics with quantum-dot and quantum-well systems

Spyridon G. Kosionis, Andreas Terzis, Seyed M. Sadeghi +1 more

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.

A. Beveratos, Izo I. Abram, Jean‐Michel Gérard +1 more

M. Bayer

Daneshfar, Nader, Foroughi, Hamidreza

In this paper, optical bistability in hybrid optomechanical systems consisting of two cavities (optomechanical and conventional) coupled to each other, which contain quantum dot molecules (QDMs), is investigated and compared. For this purpose, two different configurations are studied: in the first configuration, the quantum dot molecules (QDMs) are inside the optomechanical cavity, and in the second configuration, the quantum dot molecules are inside the conventional cavity. To calculate the dynamics of the system operators, the Heisenberg-Langevin approach is used under the mean field approximation. To achieve the phenomenon of optical bistability, which is used in optical switches and optical memories, the dynamic equations of the system are solved in a steady state. The effect of the system's physical parameters, including the detuning, the number of quantum dot molecules, and the tunneling intensity of the external field, on the phenomenon of optical bistability is studied. In addition, the switching threshold and the width of the optical bistability region in two different configurations are compared. Considering that the phenomenon of optical bistability can have potential applications in all-optical switches, optical transistors, quantum computing, and quantum communication, the obtained results can be useful for the mentioned applications and system optimization.

K. Muhammed Shafi, Wei Luo, Ramachandrarao Yalla +4 more

Recent progress in quantum nanophotonics brings novel ways for manipulating single photons in various nano-waveguides. Among them, one promising approach is to use optical nanofibres (ONFs), tapered optical fibres with sub-wavelength diameter waists. Here, we develop a hybrid system of an ONF and a single quantum dot (QD) operated at cryogenic temperatures. We deposit a single colloidal CdSe QD on an ONF waist and observe emitted photons through the fibre guided modes. We systematically investigate emission characteristics for both the neutral exciton and charged exciton (trion) for one specific QD. We quantitatively show that the trion at cryogenic temperatures acts as an excellent quantum emitter for the ONF and QD hybrid system. The present ONF/QD hybrid system at cryogenic temperatures paves the way for quantum information technologies for manipulating single photons in fibre networks.