We propose an implementation of a source of strongly sub-Poissonian light in a system consisting of a quantum dot coupled to both modes of a lossy bimodal optical cavity. When one mode of the cavity is resonantly driven with coherent light, the system will act as an efficient photon number filter, and the transmitted light will have a strongly sub-Poissonian character. In addition to numerical simulations demonstrating this effect, we present a physical explanation of the underlying mechanism. In particular, we show that the effect results from an interference between the coherent light transmitted through the resonant cavity and the super-Poissonian light generated by photoninduced tunneling. Peculiarly, this effect vanishes in the absence of the cavity loss.

The on-chip generation of nonclassical states of light is a key requirement for future optical quantum hardware. In solid-state cavity quantum electrodynamics, such nonclassical light can be generated from self-assembled quantum dots strongly coupled to photonic crystal cavities. Their anharmonic strong lightmatter interaction results in large optical nonlinearities at the single photon level, where the admission of a single photon into the cavity may enhance (photon tunneling) or diminish (photon blockade) the probability for a second photon to enter the cavity. Here, we demonstrate that detuning the cavity and quantum-dot resonances enables the generation of high-purity nonclassical light from strongly coupled systems. For specific detunings we show that not only the purity but also the efficiency of single-photon generation increases significantly, making high-quality single-photon generation by photon blockade possible with current state-of-the-art samples. [7] or epitaxially grown photonic nanowires [8] for enhanced light off-chip extraction efficiency. On the other hand, photonic crystal cavities provide a promising on-chip route toward optoelectronic integration of QDs due to the established set of associated integrated waveguide and detector structures [9,10]. Such structures will be able to exploit strong light-matter coupling with QDs for the generation of a variety of on-chip nonclassical light states by various quantum-electrodynamical (QED) methods, and recent exotic proposals have even explored the possibility of releasing energy exclusively in bundles of n photons [11]. The phenomena of photon tunneling and photon blockade in strongly coupled systems have been experimentally demonstrated both for the case of the QD on resonance [12][13][14] and near resonance [15] with the cavity (and likewise, only for resonant atom-cavity system [16]). However, in the case of large detuning these effects have only been investigated theoretically [17].In this Letter, we demonstrate the feasibility of performing photon blockade at significant detuning, and indeed the importance of doing so for high-purity and highefficiency operation. We show that by detuning the QD and cavity resonances while operating in the photonblockade regime, the second-order autocorrelation function [g ð2Þ ð0Þ] of the light transmitted through the cavity decreases from g ð2Þ ð0Þ ¼ 0.9 AE 0.05 to g ð2Þ ð0Þ ¼ 0.29 AE 0.04. Simulations of the second-and third-order autocorrelation functions for our system are in excellent agreement with the measurements, and they reveal that not only does the quality of the single photon stream increase, but that the absolute probability of obtaining a single photon increases by a factor of ∼2. Furthermore, we show that the values we obtain for g ð2Þ ð0Þ are only limited by the system parameters (QD-cavity field coupling strength g and cavity field decay rate κ), and that high-quality single-photon emission is within reach for current state-of-the-art samples for specific cavity and QD detunings.The sample i...

We investigate the influence of exciton-phonon coupling on the dynamics of a strongly coupled quantum dot-photonic crystal cavity system and explore the effects of this interaction on different schemes for nonclassical light generation. By performing time-resolved measurements, we map out the detuningdependent polariton lifetime and extract the spectrum of the polariton-to-phonon coupling with unprecedented precision. Photon-blockade experiments for different pulse-length and detuning conditions (supported by quantum optical simulations) reveal that achieving high-fidelity photon blockade requires an intricate understanding of the phonons' influence on the system dynamics. Finally, we achieve direct coherent control of the polariton states of a strongly coupled system and demonstrate that their efficient coupling to phonons can be exploited for novel concepts in high-fidelity single-photon generation.

We performed an experimental study of coupled optical cavity arrays in a photonic crystal platform. We find that the coupling between the cavities is significantly larger than the fabricationinduced disorder in the cavity frequencies. Satisfying this condition is necessary for using such cavity arrays to generate strongly correlated photons, which has potential application to the quantum simulation of many-body systems.

We use the third-and fourth-order autocorrelation functions g (3) (τ1, τ2) and g (4) (τ1, τ2, τ3) to detect the non-classical character of the light transmitted through a photonic-crystal nanocavity containing a strongly-coupled quantum dot probed with a train of coherent light pulses. We contrast the value of g (3) (0, 0) with the conventionally used g (2) (0) and demonstrate that in addition to being necessary for detecting two-photon states emitted by a low-intensity source, g (3) provides a more clear indication of the non-classical character of a light source. We also present preliminary data that demonstrates bunching in the fourth-order autocorrelation function g (4) (τ1, τ2, τ3) as the first step toward detecting three-photon states.A strongly-coupled quantum dot-cavity system can produce non-classical light by filtering the input stream of photons coming from a classical coherent light source through mechanisms described as 'photon blockade' [1,2] and 'photon-induced tunneling' [2,3]. Recent proposals [4,5] have extended the concept of photon blockade from single photons to two-photon Fock state generation by coupling the probe laser to the second manifold of the Jaynes-Cummings ladder via a two-photon transition [6]. This approach can potentially be further generalized to create third-and higher-order photon states inside the cavity through multi-photon transitions to the corresponding manifold. Following our proposal [4], we report the probing of these multi-photon transitions into the higher manifolds of the Jaynes-Cummings ladder of a strongly coupled quantum dot-photonic crystal nanocavity system [2] by measuring the third-order autocorrelation function (g (3) (τ 1 , τ 2 )) of a probe laser transmitted through such a system. Prior to this work, higherorder photon correlations had been measured for thermal [7][8][9][10] and laser [11] sources, relying on the strong excitation and high count rates available in these systems. Very recently g (3) measurements of the fluorescence from a single quantum dot weakly coupled to a microcavity were reported as well [12]. However, in the low-intensity, strongly-coupled regime of cavity quantum electrodynamics, such correlations have only been measured in an atomic system [13]. Therefore, this work constitutes a significant step towards implementing a solidstate non-classical light source of photon number states.One of the benchmarks used to characterize a source of single photons is the measurement of the the second-order autocorrelation function g (2) (τ ) = a † a † (τ )a(τ )a a † a 2[14] at τ = 0, which quantifies the suppression of multi-photon * armandhr@stanford.edu † mbajcsy@uwaterloo.ca states. In actual experiments, the value of g (2) (0) for a light source is usually estimated from a Hanbury-Brown and Twiss (HBT) setup that measures coincidence counts between two single photon counting modules (SPCMs).A classical coherent light source will produce photons with Poisson statistics (g (2) (0) = 1), while a source whose output contains at most one photon a...