In a recent work [T. C. H. Liew and V. Savona, Phys. Rev. Lett. {\bf104}, 183601 (2010)] it was numerically shown that in a photonic 'molecule' consisting of two coupled cavities, near-resonant coherent excitation could give rise to strong photon antibunching with a surprisingly weak nonlinearity. Here, we show that a subtle quantum interference effect is responsible for the predicted efficient photon blockade effect. We analytically determine the optimal on-site nonlinearity and frequency detuning between the pump field and the cavity mode. We also highlight the limitations of the proposal and its potential applications in demonstration of strongly correlated photonic systems in arrays of weakly nonlinear cavities.
We study the photon statistics of symmetric and antisymmetric modes in a photonic molecule consisting of two linearly coupled nonlinear cavity modes. Our calculations show that strong photon antibunching of both symmetric and antisymmetric modes can be obtained even when the nonlinearity in the photonic molecule is weak. The strong antibunching effect results from the destructive interference between different paths for two-photon excitation. Moreover, we find that the optimal frequency detunings for strong photon antibunching in the symmetric and antisymmetric modes are linearly dependent on …
We propose a scheme to realize strong photon antibunching with lower photon nonlinearity in a photonic molecule consisting of two photonic cavities, one of which contains a quantum dot (QD). This strong photon antibunching is attributed to destructive quantum interference effect which suppresses the two-photon excitation of the cavity field. That g^2 (0)~10^(-4) can be achieved with modest QD-cavity coupling strength g=1.1k and cavity tunneling strength J=3k when the system is driven by single laser field. To further reduce the requisite tunneling and make the system tunable, two laser fields …
We propose the use of weakly nonlinear passive materials for prospective applications in integrated quantum photonics. It is shown that strong enhancement of native optical nonlinearities by electromagnetic field confinement in photonic crystal resonators can lead to single-photon generation only exploiting the quantum interference of two coupled modes and the effect of photon blockade under resonant coherent driving. For realistic system parameters in state of the art microcavities, the efficiency of such single-photon source is theoretically characterized by means of the second-order correla…
Epitaxial quantum dots have emerged as one of the best single-photon sources, not only for applications in photonic quantum technologies but also for testing fundamental properties of quantum optics. One intriguing observation in this area is the scattering of photons with subnatural linewidth from a two-level system under resonant continuous wave excitation. In particular, an open question is whether these subnatural linewidth photons exhibit simultaneously antibunching as an evidence of single-photon emission. Here, we demonstrate that this simultaneous observation of subnatural linewidth an…
We study the photon blockade of two-photon scattering in a one-dimensional waveguide, which contains two atoms coupled via the Rydberg interaction. We obtain the analytic scattering solution of photonic wave packets with the Laplace transform method. We examine the photon correlation by addressing the two-photon relative wave function and the second-order correlation function in the single- and two-photon resonance cases. It is found that, under the single-photon resonance condition, photon bunching and antibunching can be observed in the two-photon transmission and reflection, respectively. I…
The zero-phonon transition rate of a nitrogen-vacancy center is enhanced by a factor of ~70 by coupling to a photonic crystal resonator fabricated in monocrystalline diamond using standard semiconductor fabrication techniques. Photon correlation measurements on the spectrally filtered zero-phonon line show antibunching, a signature that the collected photoluminescence is emitted primarily by a single nitrogen-vacancy center. The linewidth of the coupled nitrogen-vacancy center and the spectral diffusion are characterized using high-resolution photoluminescence and photoluminescence excitation …
Dynamic Sculpting of Photon Statistics in a Raman-Coupled Cavity QED System
Center for Quantum-Enabled Computing, Center for Theoretical Physics, Polish Academy of Sciences（波兰科学院理论与量子计算中心）；Department of Physics, Sahand University of Technology（萨汗理工大学物理系）；Department of Physics, Payame Noor University（帕亚梅诺尔大学物理系）
In recent studies [Liew et al., Phys. Rev. Lett. 104, 183601 (2010); Bamba et al., Phys. Rev. A 83, 021802(R) (2011)], due to destructive interference between different paths for two-photon excitation, strong photon antibunching can be obtained in a photonic molecule consisting of two coupled cavity modes with weak Kerr nonlinearity when one of the cavity modes is driven resonantly. Here, we study the photon statistics in a nonlinear photonic molecule with both the two cavity modes being driven coherently. We show that the statistical properties of the photons can be controlled by regulating t…
We study the unconventional photon blockade, recently proposed for a coupled-cavity system, in presence of input and output quantum fields. Mixing of the input or output channels still allows strong photon antibunching of the output field, but for optimal values of the system parameters that differ substantially from those that maximize antibunching of the intracavity field. This result shows that the specific input-output geometry in a photonic system determines the optimal design in view of single-photon device operation. We provide a compact analytical formula that allows finding the optima…
We propose a scheme for the resonant generation of counter-polarized single photons in double asymmetric cavities with a small Kerr optical nonlinearity (as that created by a semiconductor quantum well) compared to the mode broadening. Due to the interplay between spatial intercavity tunneling and polarization coupling, by weakly exciting with circularly polarized light one of the cavities, we predict strong antibunching of counter-polarized light emission from the non-pumped auxiliary cavity. This scheme due to quantum interference is robust against surface scattering of pumping light, which …
Photon antibunching in the light scattered by single quantum emitters is one of the hallmarks of quantum optics, providing an unequivocal demonstration of the quantized nature of the electromagnetic field. Antibunching can be intuitively understood by the need for a two-level system lying in its lower state after emitting a photon to be re-excited into the upper one before a second emission can take place. Here we show that such a picture breaks down in the ultrastrong light-matter coupling regime, when the coupling strength becomes comparable to the bare emitter frequency. Specialising to the…
Quantum walk represents one of the most promising resources for the simulation of physical quantum systems, and has also emerged as an alternative to the standard circuit model for quantum computing. Up to now the experimental implementations have been restricted to single particle quantum walk, while very recently the quantum walks of two identical photons have been reported. Here, for the first time, we investigate how the particle statistics, either bosonic or fermionic, influences a two-particle discrete quantum walk. Such experiment has been realized by adopting two-photon entangled state…
This thesis is devoted to the study of the coupling of single-photon emitters with photonic nanostructures by using the properties of the near field of a photonic structure in view of the realization of a compact integrated single-photon source for quantum applications. The first part of my thesis work was consecrated to the optimization of perovskites nanocrystals. Although perovskites nanocrystals are very promising single-photon sources, they still need improvements: in this work, I review the main properties of these emitters and present a full characterization of perovskite nanocrystals w…
We introduce a scheme of single photon emission based on four-wave mixing in a three mode system with weak Kerr-type nonlinearity. A highly populated lower energy mode results in strong stimulated scattering of particle pairs out of the central mode, which consequently limits the central mode occupation. Thus, the system can be reduced to a $χ^{(2)}$ nonlinear medium with greatly enhanced interaction constant. As a model setup we consider dipolaritons in semiconductor microcavities. Using the master equation approach we show strong antibunching under continuous wave pump, which largely exceeds…
We theoretically study the emission statistics of a weakly nonlinear photonic dimer during coherent oscillations. We show that the phase and population dynamics allow to periodically meet an optimal intensity squeezing condition resulting in a strongly nonclassical emission statistics. By considering an exciton-polariton Josephson junction resonantly driven by a classical source, we show that a sizeable antibunching should emerge in such semiconductor system where intrinsic nonclassical signatures have remained elusive to date.
We observe a sixfold Purcell broadening of the D$_2$ line of an optically trapped $^{87}\text{Rb}$ atom strongly coupled to a fiber cavity. Under external illumination by a near-resonant laser, up to $90\%$ of the atom's fluorescence is emitted into the resonant cavity mode. The sub-Poissonian statistics of the cavity output and the Purcell enhancement of the atomic decay rate are confirmed by the observation of a strongly narrowed antibunching dip in the photon autocorrelation function. The photon leakage through the higher-transmission mirror of the single-sided resonator is the dominant con…
We analyze the creation and emission of pairs of highly nonclassical microwave photons in a setup where a voltage-biased Josephson junction is connected in series to two electromagnetic oscillators. Tuning the external voltage such that the Josephson frequency equals the sum of the two mode frequencies, each tunneling Cooper pair creates one additional photon in both of the two oscillators. The time-resolved statistics of photon emission events from the two oscillators is investigated by means of single- and cross-oscillator variants of the second-order correlation function $g^{(2)}(τ)$ and th…
Colloidal core/shell InP/ZnSe quantum dots (QDs), recently produced using an improved synthesis method, have a great potential in life-science applications as well as in integrated quantum photonics and quantum information processing as single-photon emitters. Single-particle spectroscopy of 10-nm QDs with 3.2-nm cores reveals strong photon antibunching attributed to fast (70-ps) Auger recombination of multiple excitons. The QDs exhibit very good photostability under strong optical excitation. We demonstrate that the antibunching is preserved when the QDs are excited above the saturation inten…
Quantum photonic chips, which integrate quantum light sources alongside active and passive optical elements, as well as single photon detectors, show great potential for photonic quantum information processing and quantum technology. Mature semiconductor nanofabrication processes allow for scaling such photonic integrated circuits to on-chip networks of increasing complexity. Second order nonlinear materials are the method of choice for generating photonic quantum states in the overwhelming part of linear optic experiments using bulk components but integration with waveguide circuitry on a nan…
Optical non-linearities at the single-photon level are key ingredients for future photonic quantum technologies. Prime candidates for the realization of strong photon-photon interactions necessary for implementing quantum information processing tasks as well as for studying strongly correlated photons in an integrated photonic device setting are quantum dots embedded in photonic crystal nanocavities. Here, we report strong quantum correlations between photons on picosecond timescales. We observe (a) photon antibunching upon resonant excitation of the lowest-energy polariton state, proving that…
Modeling the Quantum Photon Statistics in Hybrid Light-Matter Integrated Circuits
Hewlett Packard Labs（惠普实验室）；Institute of Nanotechnology, National Research Council（国家研究委员会纳米技术研究所）；Institute of Semiconductor and Solid State Physics, Johannes Kepler University（约翰内斯开普勒大学半导体与固态物理研究所）
Although our understanding of Bell's theorem and experimental techniques to test it have improved over the last 40 years, thus far all Bell tests have suffered at least from the detection or the locality loophole. Most photonic Bell tests rely on inefficient discrete-outcome measurements, often provided by photon counting detection. One possible way to close the detection loophole in photonic Bell tests is to involve efficient continuous-variable measurements instead, such as homodyne detection. Here, we propose a test of the Clauser-Horne-Shimony-Holt (CHSH) inequality that applies photon cou…
We propose an atom-cavity chip that combines laser cooling and trapping of neutral atoms with magnetic microtraps and waveguides to deliver a cold atom to the mode of a fiber taper coupled photonic bandgap (PBG) cavity. The feasibility of this device for detecting single atoms is analyzed using both a semi-classical treatment and an unconditional master equation approach. Single-atom detection seems achievable in an initial experiment involving the non-deterministic delivery of weakly trapped atoms into the mode of the PBG cavity.
We propose a novel scheme for realizing single-photon blockade in a weakly driven hybrid cavity optomechanical system consisting of a nonlinear photonic crystal. Sub-Poissonian statistics is realized even when the single-photon optomechanical coupling strength is smaller than the decay rate of the optical mode. The scheme relaxes the requirement of strong coupling for photon blockade in optomechanical systems. It is shown that photon blockade could be generated at the telecommunication wavelength.
We consider the estimation of a Hamiltonian parameter of a set of highly photosensitive samples, which are damaged after a few photons $N_{\rm abs}$ are absorbed, for a total time $T$. The samples are modelled as a two mode photonic system, where photons simultaneously acquire information on the unknown parameter and are absorbed at a fixed rate. We show that arbitrarily intense coherent states can obtain information at a rate that scales at most linearly with $N_{\rm abs}$ and $T$, whereas quantum states with finite intensity can overcome this bound. We characterise the quantum advantage as a…
We extend the idea of quantum phase transitions of light in the photonic Bose-Hubbard model with interactions to two atomic species by a self-consistent mean field theory. The excitation of two-level atoms interacting with coherent photon fields is analyzed with a finite temperature dependence of the order parameters. Four ground states of the system are found, including an isolated Mott-insulator phase and three different superfluid phases. Like two weakly coupled superconductors, our proposed dual-species lattice system shows a photonic analogue of Josephson effect. The dynamics of the propo…
We report on the control of the spontaneous emission dynamics from InAsP self-assembled quantum dots emitting in the telecommunications C-band and weakly coupled to the mode of a double heterostructure cavity etched on a suspended InP membrane at room temperature. The quality factor of the cavity mode is 44x10^3 with an ultra-low modal volume of the order of 1.2 lambda/n)^3, inducing an enhancement of the spontaneous emission rate of up a factor of 2.8 at 300 K.
Photon statistics in a weakly driven optomechanical photonic crystal cavity, with Kerr-type nonlinearity, is analyzed both analytically and numerically. Single-photon blockade effect is demonstrated via calculations of the zero-time-delay second-order correlation function $g^{(2)}(0)$. The analytical results obtained by solving the Schrödinger equation are in complete conformity with the results obtained through numerical solution of the quantum master equation. The experimental feasibility with state-of-the-art device parameters is discussed. It is observed that photon blockade could be gener…
Single-photon sources are essential building blocks in quantum photonic networks, where quantum-mechanical properties of photons are utilised to achieve quantum technologies such as quantum cryptography and quantum computing. Most conventional solid-state single-photon sources are based on single emitters such as self-assembled quantum dots, which are created at random locations and require spectral filtering. These issues hinder the integration of a single-photon source into a scaleable photonic quantum network for applications such as on-chip photonic quantum processors. In this work, using …
In the recent publications [Phys. Rev. A 92,023838 (2015)], the unconventional photon blockade are studied in a two-mode-second-order-nonlinear system with nonlinear coupling between the low frequency and high frequency modes. In this paper, we study the unconventional photon blockade in a three-mode system with weakly coupled nonlinear cavities via $χ^{(2)}$ nonlinearity. By solving the master equation in the steady-state limit and calculating the zero-delay time second-order correlation function, we obtain the conditions of strong photon antibunching in the low frequency mode. The numerical …
We propose an experimental scheme to generate, in a heralded fashion, arbitrary quantum superpositions of two-mode optical states with a fixed total photon number $n$ based on weakly squeezed two-mode squeezed state resources (obtained via weak parametric down conversion), linear optics, and photon detection. Arbitrary $d$-level (qudit) states can be created this way where $d=n+1$. Furthermore, we experimentally demonstrate our scheme for $n=2$. The resulting qutrit states are characterized via optical homodyne tomography. We also discuss possible extensions to more than two modes concluding t…
Photons in a nonlinear medium can repel or attract each other, resulting in a strongly correlated quantum many-body system. Typically, such strongly correlated states of light arise from the extreme nonlinearity granted by quantum emitters that are strongly coupled to a photonic mode. However, in these approaches, unavoidable dissipation, like photon loss, blurs nonlinear quantum effects. Here, we generate strongly correlated photon states using only weak coupling and taking advantage of dissipation. We launch light through an ensemble of non-interacting waveguide-coupled atoms, which induce c…
Nanyang Technological University（南洋理工大学）；MajuLab, International Joint Research Unit UMI 3654, CNRS, Université Côte d’Azur, Sorbonne Université, National University of Singapore, Nanyang Technological University, Singapore（MajuLab，国际联合研究单位UMI 3654，法国国家科学研究中心，蔚蓝海岸大学，索邦大学，新加坡国立大学，南洋理工大学）；Centre for Disruptive Photonic Technologies（颠覆性光子技术中心）
Interfacing solid-state emitters with photonic structures is a key strategy for developing highly efficient photonic quantum technologies. Such structures are often organised into two distinct categories: nanocavities and waveguides. However, any realistic nanocavity structure simultaneously has characteristics of both a cavity and waveguide, which is particularly pronounced when the cavity is constructed using low-reflectivity mirrors in a waveguide structure with good transverse light confinement. In this regime, standard cavity quantum optics theory breaks down, as the waveguide character o…
Bosonic statistics enhance Maxwell's demon in photonic experiment
MESA+ Institute for Nanotechnology, University of Twente（特温特大学 MESA+ 纳米技术研究所）；Joint Center for Quantum Information and Computer Science, NIST and University of Maryland（美国国家标准与技术研究院与马里兰大学量子信息与计算机科学联合中心）；Department of Physics, University of Maryland（马里兰大学物理系）；Department of Physics and Astronomy, University of Rochester（罗切斯特大学物理与天文学系）；Institute for Physical Science and Technology, University of Maryland（马里兰大学物理科学与技术研究所）
We show that very large nonlocal nonlinear interactions between pairs of colliding slow-light pulses can be realized in atomic vapors in the regime of electromagnetically induced transparency. These nonlinearities are mediated by strong, long-range dipole--dipole interactions between Rydberg states of the multi-level atoms in a ladder configuration. In contrast to previously studied schemes, this mechanism can yield a homogeneous conditional phase shift of pi even for weakly focused single-photon pulses, thereby allowing a deterministic realization of the photonic phase gate.
We propose a single photon source based on a pair of weakly nonlinear optical cavities subject to a one-directional dissipative coupling. When both cavities are driven by mutually coherent fields, sub-poissonian light is generated in the target cavity even when the nonlinear energy per photon is much smaller than the dissipation rate. The sub-poissonian character of the field holds over a delay measured by the inverse photon lifetime, as in the conventional photon blockade, thus allowing single-photon emission under pulsed excitation. We discuss a possible implementation of the dissipative cou…
