arXiv:quant-ph/0211144

Quantum optical phenomena in semiconductor quantum dots

J. T. Andrews

Published Nov 22, 2002• 0 citations

Abstract

Quantum optical phenomena are explored in artificial atoms well known as semiconductor quantum dots, in the presence of excitons and biexcitons. The analytical results are obtained using the conventional time-dependent perturbation technique. Numerical estimations are made for arealistic sample of CdS quantum dots in a high-Q cavity. Quantum optical phenomena such as quantum Rabi oscillations, photon statistics and collapse and revival of population inversion in exciton and biexciton states are observed. In the presence of biexcitons the collapse and revival phenomenon becomes faster due to the strong coupling of biexciton with cavity field.

DOI: 10.48550/arxiv.quant-ph/0211144

Related papers

Depolarization-induced modification of Rabi oscillations in a semiconductor quantum dot

A. Magyarov, Gregory Ya. Slepyan, С. А. Максименко

A theory of the nonlinear interaction between a single quantum dot (QD) and electromagnetic fields, accounting the QD-depolarization (local-field) has been developed. QD excitation by classical and quantum electromagnetic fields such as coherent state of light, Fock qubit and gaussian excitation has been considered. As a result, for the case of the QD illuminated by coherent states of light, we predict the appearance of two oscillatory regimes in the Rabi oscillations. In the first one, signatures of Rabi oscillations are found to be suppressed: the population inversion is negative and the conventional collapse-revivals phenomenon is absent, while in the second one the collapse and revivals are appeared, showing significant difference as compared to those predicted within the standard Jaynes-Cummins theory. Under the pulsed excitation, Rabi oscillation dynamics is found to be strongly depended on the input pulse area and duration.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIEJun 15, 20070 citations

Theory of Exciton Coherence and Decoherence in Semiconductor Quantum Dots

T. Takagahara

We discuss the Rabi splitting and Rabi oscillation of excitons in semiconductor quantum dots and clarify the fundamental physics and new characteristic features. These coherent optical phenomena are not restricted to semiconductor quantum dots and the predicted features would be observed also in atoms and molecules. The universality of the phenomena ensures the possibility for application to quantum state control and quantum information processing by optical means. We discuss briefly the mechanisms of exciton dephasing in semiconductor quantum dots in conjunction with recent observations of the lifetime-limited exciton dephasing time and show that the pure dephasing rate is very small but is not vanishing even at zero Kelvin.

physica status solidi (b)Nov 1, 20027 citations

Nonlinear Rabi Oscillations of Excitons in Dense Quantum Dot System

Yasuyoshi Mitsumori, Atsushi Hasegawa, Sasaki, M. +2 more

Nonlinear optical response and optical coherence of excitons in semiconductor dense quantum dots in GaAs single quantum wells has been studied by using photon echo techniques. At low temperatures, the optical coherence is estimated to be 2 ns from the decay curve in the photon echo signal. Rabi oscillations are also observed. Unlike the results for a single quantum dot in the literature to date, the oscillation shows nonlinear behavior affected strongly by the pre-excited carrier density. The results can be explained by the theory of the local field correction originating from exciton-exciton interaction between the inter dots.

arXiv:cond-mat/0306086Jun 4, 20030 citations

Quantum light generation and imaging using quantum dots

Robert James Young

Semiconductor Quantum dots are potentially an attractive source of non-classical light. They can confine bound electron-hole pairs, excitons, in all three spatial dimensions giving them discrete optical emission energies, much like the electronic states in atomic systems. The semiconductor nature of the system allows quantum dots to be integrated into complicated device structures including optical cavities [1] and electrical injection [2]. The radiative exciton emission from a semiconductor quantum dot can provide the simplest form of quantum light, a single photon source [2]. The finite re-excitation time following the radiative decay of an exciton in a quantum dot prevents the dot from emitting more than one photon if excited with a short optical or electronic pulse. In a similar fashion excitation of the biexciton state, consisting of two electrons and holes, in the quantum dot results in the emission of a pair of photons at the energy of the biexciton and exciton transitions. The biexciton state was, in fact, proposed as a possible source of polarisation-entangled photons in 2000 by Benson et al. [3] as it consists of two polarisation-correlated decay paths which could potentially be indistinguishable. The condition of indistinguishability is fundamental to the generation of entangled photons and is, in general, not true of the two decay paths from the biexciton state in a quantum dot; physical anisotropy causes the intermediate exciton states to hybridise and separate in energy providing ‘which-path’ information about the route taken through the biexciton decay. We demonstrate how the splitting between the intermediate exciton states in a single InAs quantum dot can be controlled by growth [4], rapid thermal annealing [5] and the application of an external magnetic field [6]. Each of these three techniques can be used to make the intermediate exciton states degenerate allowing the biexciton decay to produce singe pairs of entangled photons triggered by short laser pulses [7,8]. Entangled photon pair sources are essential for applications such as entanglement based quantum key distribution, and optical quantum computing. For these applications it is important that no more than one entangled photon pair is generated in a cycle, a requirement met by our quantum dot source which is not possible with traditional methods for generating entangled pairs of photons. Entanglement also enables quantum interferometry and metrology, the basis of image resolution beyond that possible with equivalent classical light. Biphoton interferometry using entangled emission from the biexciton decay reveals fringes with half the period of classical light [9], and less that that of the laser. In addition, interferometry suggests that this type of entangled light source is not limited by decoherence, we fine the biphoton is surprising robust against dephasing, in stark contrast to the devastating effect of decoherence upon single photons emitted by similar structures.

Jun 4, 20070 citations

Exciton absorption properties of coherently coupled exciton-biexciton systems in quantum dots

Hideki Gotoh, Hidehiko Kamada, Tadashi Saitoh +2 more

Exciton-biexciton coherent coupling effects are examined in semiconductor quantum dots. The exciton absorption spectrum is measured with the microphotoluminescence excitation technique in a single InGaAs quantum dot. The spectrum changes from a Lorenztian-type line shape to an unusual dip-shaped line shape with increasing excitation intensities in a higher exciton state where there is a large oscillator strength between the exciton and biexciton states. The intensity dependence of the dip energy width clearly indicates that coherent Rabi oscillation occurs between the exciton and biexciton states. The absorption properties with excitation light of different polarizations show that the dip-shaped spectra only appear when there is a large biexciton state population with linear polarization. A theoretical analysis undertaken with the density matrix method agrees well with experimental results. This agreement reveals that exciton-biexciton coherent interactions lead to unusual absorption spectra and contribute crucially to the optical properties of quantum dots. The exciton-biexciton coherent effects provide a scheme for controlling four distinguishable states, which can be applied to a demonstration of quantum gate operations.

Physical Review BMay 1, 200523 citations

Single-photon nonlinearity of a semiconductor quantum dot in a cavity

D. Sanvitto, Fabrice P. Laussy, Frank Bello +6 more

A single atom in a cavity is the model system of cavity quantum electrodynamics (CQED). The strong coupling regime between the atom and cavity-confined photon corresponds to the reversible exchange of energy between the two modes, and underpins a wide range of CQED phenomena with applications in quantum information science, including for example as quantum logic gates and as sources of entangled states. An important advance was achieved recently when strong coupling between excitons and cavity photons was reported for the first time for localized quantum dots (QDs) in micron-size solid state cavities. This has significance in terms of scalability and integration with other optical devices, and could lead to the emergence of "quantum optics on a chip" technology. However the results presented so far for quantum dots are in the linear regime, corresponding to coupling to the vacuum field (vacuum Rabi splitting); they are not a true QED effect and can equally well be described by classical physics as the coupling between two oscillators. In this paper, we present evidence for a purely quantum phenomenon for the QD/cavity photon system, namely the increase in splitting of the levels when the mean number of photons in the cavity is increased. This corresponds to non-linearities on the single-photon scale: the presence of a single excitation in the cavity changes the level structure, affecting the emission energies for a second photon. Such results are a first step in demonstrating the promise of quantum dots for CQED applications.

arXiv:cond-mat/0612034Dec 1, 20060 citations