We propose and characterize a two-photon emitter in a highly polarised, monochromatic and directional beam, realized by means of a quantum dot embedded in a linearly polarized cavity. In our scheme, the cavity frequency is tuned to half the frequency of the biexciton (two excitons with opposite spins) and largely detuned from the excitons thanks to the large biexciton binding energy. We show how the emission can be Purcell enhanced by several orders of magnitude into the two-photon channel for available experimental systems.
We show that it is possible to realize quantum superpositions of switched-on and -off strong light-matter interaction in a single quantum dot- semiconductor microcavity system. Such superpositions enable the observation of counterintuitive quantum conditional dynamics effects. Situations are possible where cavity photons as well as the emitter luminescence display exponential decay but their joint detection probability exhibits vacuum Rabi oscillations. Remarkably, these quantum correlations are also present in the nonequilibrium steady state spectra of such coherently driven dissipative quant…
We investigate the strong coupling regime of a self-assembled quantum dot in a tunable microcavity with dark-field laser spectroscopy. The high quality of the spectra allows the lineshapes to be analyzed revealing subtle quantum interferences. Agreement with a model calculation is achieved only by including exciton dephasing which reduces the cooperativity from a bare value of 9.0 to the time-averaged value 5.5. In the pursuit of high cooperativity, besides a high-Q and low mode-volume cavity, we demonstrate that equal efforts need to be taken towards lifetime-limited emitter linewidths.
We report the efficient coherent photon scattering from a semiconductor quantum dot embedded in a pillar microcavity. We show that a surface acoustic wave can periodically modulate the energy levels of the quantum dot, but has a negligible effect on the cavity mode. The scattered narrow-band laser is converted to a pulsed single-photon stream, displaying an anti-bunching dip characteristic of single-photon emission. Multiple phonon sidebands are resolved in the emission spectrum, due to the absorption and emission of vibrational quanta in each scattering event.
We demonstrate the emission of highly indistinguishable photons from a quasi-resonantly pumped coupled quantum dot--microcavity system operating in the regime of cavity quantum electrodynamics. Changing the sample temperature allows us to vary the quantum dot--cavity detuning, and on spectral resonance we observe a three-fold improvement in the Hong--Ou--Mandel interference visibility, reaching values in excess of 80\%. Our measurements off-resonance allow us to investigate varying Purcell enhancements, and to probe the dephasing environment at different temperatures and energy scales. By comp…
The future of quantum communication systems and quantum networks heavily rely on the ability to fabricate and coherently control the conversion of photons between different modes based on a solid-state plateform. In this work, we propose and theoretically investigate a scheme to optomechanically control coherent mode conversion of optical photons by utilizing two optically coupled hybrid semiconductor microcavities containing a quantum dot (QD). One of the microcavity is pumped by an external laser and the second cavity is driven by light emitted by the QD that is embedded in the interface sep…
We theoretically explore optical bistability for possible signature of all optical switching and their performance in a hybrid quantum optomechanical system comprising of two semiconductor microcavity coupled optically. One of the cavity is driven by an external optical pump laser while the second cavity which contains a quantum dot is indirectly driven by light transmitted from the first cavity. The generated bistable behavior due to optomechanical nonlinearity shows a typical optical switching behavior and it can be controlled by changing the laser power, QD cavity coupling, rocking paramete…
In this paper we introduce and analyze a new system design for quantum-dot-based qubits that simultaneously supports scalable one-qubit and two-qubit gates, and single-shot qubit measurement. All three key processes (one-qubit gates, two-qubit gates, and qubit measurement) rely on the interaction between the electron in each quantum dot and exciton-polaritons formed in a quantum well situated near the quantum dots. A key novel feature of our proposed system is the use of polariton traps, which we show enhances the quantum-dot--quantum-well interaction by a factor of 10 and consequently results…
We theoretically investigate optical bistability, mechanically induced absorption (MIA) and Fano resonance of a hybrid system comprising of a single quantum dot (QD) embedded in a solid state microcavity interacting with the quantized cavity mode and the deformation potential associated with the lattice vibration. We find that the bistability can be tuned by the QD-cavity mode coupling. We further show that the normalized power transmission displays anomalous dispersion indicating that the system can be used to generate slow light. We also demonstrate the possibility of using the system as all…
We propose a scheme to realize a highly efficient solid state source of photon pairs using cavity-assisted stimulated Raman adiabatic passage (STIRAP) in a single quantum dot, where a single photon from pump pulse and two stokes photons from cavity mode drives the Raman transition. The Autler-Townes doublet, generated by using a resonant continuous wave laser between biexciton and exciton states, and two-photon-resonant transition through strongly coupled cavity mode are utilized to facilitate (1+2)type Raman transition in the quantum dot. We show in the case of weak pump although the probabil…
Fundamental properties of the spin-noise signal formation in a quantum-dot microcavity are studied by measuring the angular characteristics of the scattered light intensity. A distributed Bragg reflector microcavity was used to enhance the light-matter interaction with an ensemble of n-doped (In,Ga)As/GaAs quantum dots, which allowed us to study subtle effects of the noise signal formation. Detecting the scattered light outside of the aperture of the transmitted light, we measured the basic electron spin properties, like g-factor and spin dephasing time. Further, we investigated the influence …
Semiconductor quantum-dot cavity systems are promising sources for solid-state based on-demand generation of single photons for quantum communication. Commonly, the spectral characteristics of the emitted single photon are fixed by system properties such as electronic transition energies and spectral properties of the cavity. In the present work we study single-photon generation from the quantum-dot biexciton through a partly stimulated non-degenerate two-photon emission. We show that frequency and linewidth of the single photon can be fully controlled by the stimulating laser pulse, ultimatel…
We explore the tunneling transport properties of a quantum dot embedded in an optical microcavity and coupled to a semiconductor-superconductor one-dimensional nanowire (Majorana nanowire) hosting Majorana zero modes (MZMs) at their edges. Conductance profiles reveal that strong light-matter coupling can be employed to distinguish between the cases of highly nonlocal MZMs, overlapped MZMs and MZMs with less degree of nonlocal feature. Moreover, we show that it is possible to access the degree of Majorana nonlocality (topological quality factor) by changing the dot spectrum through photon-induc…
En este trabajo, se obtiene una expresión numérica para calcular el espectro de emisión de un sistema microcavidad-punto cuántico usando una teoría de campo medio en el formalismo de la matriz densidad. El sistema modelado es un micropilar semiconductor que contiene un único punto cuántico en el interior de la microcavidad, este sistema presenta pérdida de fotones a través de los espejos de la cavidad y bombeo de excitones al punto cuántico. Obtenemos una ecuación maestra de campo medio no lineal que nos permite calcular el espectro de emisión. In this work, we deduce a numerical expression to…
We discuss the generation of two types of entangled state of two photons-- noon state which is entangled in number and polarization, and polarization entangled state which is entangled in polarization and frequency. We consider a single quantum dot coupled with a bimodal cavity in strong coupling regime. We analyze the effect of exciton-phonon coupling on the concurrence of the generated entangled states. We find that for both states concurrence is maximum in the absence of the anisotropic energy gap between exciton states and remains unchanged in the presence of exciton-phonon coupling. Howev…
We study experimentally and theoretically a coherently-driven strongly-coupled quantum dot-microcavity system. Our focus is on physics of the unexplored intermediate excitation regime where the resonant laser field dresses a strongly-coupled single exciton-photon (polariton) system resulting in a ladder of laser-dressed Jaynes-Cummings states. In that case both the coupling of the emitter to the confined light field of the microcavity and to the light field of the external laser are equally important, as proved by observation of injection pulling of the polariton branches by an external laser.…
Polariton emission from optical cavities integrated with various luminophores has been extensively studied recently due to the wide variety of possible applications in photonics, particularly promising in terms of fabrication of low-threshold sources of coherent emission. Tuneable microcavities allow extensive investigation of the photophysical properties of matter placed inside the cavity by deterministically changing the coupling strength and controllable switching from weak to strong and ultra-strong coupling regimes. Here we demonstrate room temperature strong coupling of exciton transitio…
We theoretically investigate the nonlinear effects in a hybrid quantum optomechanical system consisting of two optically coupled semiconductor microcavities containing a quantum dot and a Kerr nonlinear substrate.The steady state behavior of the mean intracavity optical field demonstrates that the system can be used as an all optical switch. We further investigate the spectrum of small fluctuations in the mechanical displacement of the movable distributed Bragg reflectors (DBR) and observe that normal mode splitting (NMS) takes place for high Kerr nonlinearity and pump power. In addition, we h…
We report on the coherent optical response from an ensemble of (In,Ga)As quantum dots (QDs) embedded in a planar Tamm-plasmon microcavity with a quality factor of approx. 100. Significant enhancement of the light-matter interaction is demonstrated under selective laser excitation of those quantum dots which are in resonance with the cavity mode. The enhancement is manifested through Rabi oscillations of the photon echo, demonstrating coherent control of excitons with picosecond pulses at intensity levels more than an order of magnitude smaller as compared with bare quantum dots. The decay of t…
The Jaynes-Cummings (JC) model represents one of the simplest ways in which single qubits can interact with single photon modes, leading to profound quantum phenomena like superpositions of light and matter states. One system, that can be described with the JC model, is a single quantum dot embedded in a micropillar cavity. In this joint experimental and theoretical study we investigate such a system using four-wave mixing (FWM) micro-spectroscopy. Special emphasis is laid on the dependence of the FWM signals on the number of photons injected into the microcavity. By comparing simulation and e…
Dipolaritons are quasiparticles that arise in coupled quantum wells embedded in a microcavity, they are a superposition of a photon, a direct exciton and an indirect exciton. We propose the existence of dipolaritons in a system of two coupled quantum dots inside a microcavity in direct analogy with the quantum well case and find that, despite some similarities, dipolaritons in quantum dots have different properties and can lead to true dark polariton states. We use a finite system theory to study the effects of the magnetic field on the system, including the emission, and find that it can be u…
In this note we present some results concerning photon blockade and antibunching in a system consisting of a quantum dot embedded in a microcavity. We give analytic conditions for resonant and non-resonant photon blockade, valid for small values of the external pump amplitude. Starting from these results, we discuss the quantum states characteristics of the system within a master equation formalism and highlight quantities like stationary second order correlations both static and dynamic and one-photon purity.
