Nonlinear photoluminescence spectra from a quantum-dot–cavity system: Interplay of pump-induced stimulated emission and anharmonic cavity QED (original) (raw)
Related papers
Cavity versus dot emission in strongly coupled quantum dots-cavity systems
2011
We discuss the spectral lineshapes of N quantum dots in strong coupling with the single mode of a microcavity. Nontrivial features are brought by detuning the emitters or probing the direct exciton emission spectrum. We describe dark states, quantum nonlinearities, emission dips and interferences and show how these various effects may coexist, giving rise to highly peculiar lineshapes.
We refute the criticisms of our work on strong-coupling in the presence of an incoherent pumping. Our description of strong-coupling in semiconductors [1, 2, 3] has been recently criticized by two groups: Ridolfo et al. [4] and Yao et al. [5]. Both groups of authors make the same statements: they claim that our master equation is flawed, on the ground that its domain of convergence is bounded, they both propose to use exclusively a thermal bath for the reservoir of excitations of the cavity instead of our most general case (Yao et al. require a thermal bath also for the excitonic reservoir whereas Ridolfo et al. allow independent pumping and decay coefficients for the Quantum Dot (QD)) and they all claim a better agreement than our model with experimental data. We show in this comment that their criticisms are erroneous and that the alternatives they propose to fulfill them are well known particular cases that, in their approximations, are also erroneous.
Coherent excitation of a strongly coupled quantum dot - cavity system
2009
We have studied the coherent excitation of a strongly coupled QD/photonic crystal cavity system. Time-resolved reflectivity measurements show the vacuum Rabi oscillation of the dot in the cavity. Next, we considered the resonant driving of a cavity-detuned dot, which efficiently populates the cavity mode. This cavity-controlled read-out channel allows high-resolution single quantum dot spectroscopy. Autocorrelation measurements on the cavity mode show antibunching and suggest the use of the resonantly driven QD/cavity system as an on-demand source of single photons with potentially near-unity indistinguishability.
Effective cavity pumping from weakly coupled quantum dots
2011
We derive the effective cavity pumping and decay rates for the master equation of a quantum dot-microcavity system in presence of N weakly coupled dots. We show that the inflow of photons is not linked to the out-flow by thermal equilibrium relationships.
Single-photon nonlinearity of a semiconductor quantum dot in a cavity
2006
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. 2,3,4 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, 5-8 . 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. 9 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.
2010
We compare the photoluminescence spectrum of an indium arsenide (InAs) quantum dot (QD) that is strongly coupled to a photonic crystal cavity under above band excitation (ABE) and quasi-resonant excitation (QRE). We show that off-resonant cavity feeding, which manifests itself in a bare cavity emission peak at the strong coupling point, is suppressed by as much as 40% under QRE relative to ABE. We attribute this suppression to a reduced probability of QD charging because electrons and holes are created in pairs inside the QD. We investigate the pump power dependence of the cavity feeding and show that, below saturation, the ratio of the bare cavity emission to polariton emission for ABE is independent of pump power, while for QRE there is linear pump power dependence. These results suggest that the biexciton plays an important role in cavity feeding for QRE.
Optics Express, 2009
A strongly coupled quantum dot-micropillar cavity system is studied under variation of the excitation power. The characteristic double peak spectral shape of the emission with a vacuum Rabi splitting of 85 μeV at low excitation transforms gradually into a single broad emission peak when the excitation power is increased. Modelling the experimental data by a recently published formalism [Laussy et al., Phys. Rev. Lett. 101, 083601 (2008)] yields a transition from strong coupling towards weak coupling which is mainly attributed to an excitation power driven decrease of the exciton-photon coupling constant.
The Role of a Polariton Bath in the Emission Spectrum of an Open Nanocavity-Quantum Dot System
2012
We investigate the effect of a polariton bath on the photoluminescence (PL) spectrum of the elementary excitations for a confined nanocavity-quantum dot (nC-QD) system. We modeled the nC-QD system as a two-level exciton in strong coupling with a single photonic cavity mode interacting with its environment. The non-hamiltonian processes induced by the environment are taken into account via a Born-Markov master equation which includes: gain and loss of excitons and photons into/out of the cavity, a dephasing mechanism produced by phonon scattering in the semiconductor lattice and gain and loss of polaritons due to the already mentioned polariton bath. In order to validate our phenomenological model, we fit an experimental spectrum to extract the values of all parameters appearing in the master equation. Our results show that polariton pumping and loss rates are comparable to the other parameters and therefore we have a first evidence that the polariton bath we proposed has a significant role in the dynamics of a nC-QD system.