Nonequilibrium Prethermal States in a Two-Dimensional Photon Fluid

Phys. Rev. Lett. 129, 100602 (2022)

Nonequilibrium Prethermal States in a Two-Dimensional Photon Fluid

Phys. Rev. Lett. 129, 100602 (2022)

Analogue cosmological particle creation in an ultracold quantum fluid of light

Nature Communications 13, 1--7 (2022)

High-Resolution Coherent Probe Spectroscopy of a Polariton Quantum Fluid

Phys. Rev. Lett. 129, 103601 (2022)

Measurement of the Static Structure Factor in a Paraxial Fluid of Light Using Bragg-like Spectroscopy

Phys. Rev. Lett. 127, 023401 (2021)

Quantitative Analysis of Shock Wave Dynamics in a Fluid of Light

Phys. Rev. Lett. 126, 183901 (2021)

Analogue quantum simulation of the Hawking effect in a polariton superfluid

Jacquet, Maxime and Joly, Malo and Claude, Ferdinand and Giacomelli, Luca and Glorieux, Quentin and Bramati, Alberto and Carusotto, Iacopo and Giacobino, Elisabeth

The European Physical Journal D 76, 1--15 (2022)

Analogue quantum simulation of the Hawking effect in a polariton superfluid

Quantum effects of fields on curved spacetimes may be studied in the laboratory thanks to quantum fluids. Here we use a polariton fluid to study the Hawking effect, the correlated emission from the quantum vacuum at the acoustic horizon. We show how out-of-equilibrium physics affects the dispersion relation, and hence the emission and propagation of correlated waves: the fluid properties on either side of the horizon are critical to observing the Hawking effect. We find that emission may be optimised by supporting the phase and density of the fluid upstream of the horizon in a regime of optical bistability. This opens new avenues for the observation of the Hawking effect in out-of-equilibrium systems as well as for the study of new phenomenology of fields on curved spacetimes.

High-Resolution Coherent Probe Spectroscopy of a Polariton Quantum Fluid

Claude, F. and Jacquet, M. J. and Usciati, R. and Carusotto, I. and Giacobino, E. and Bramati, A. and Glorieux, Q.

Phys. Rev. Lett. 129, 103601 (2022)

High-Resolution Coherent Probe Spectroscopy of a Polariton Quantum Fluid

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Analogue cosmological particle creation in an ultracold quantum fluid of light

Steinhauer, Jeff and Abuzarli, Murad and Aladjidi, Tangui and Bienaimé, Tom and Piekarski, Clara and Liu, Wei and Giacobino, Elisabeth and Bramati, Alberto and Glorieux, Quentin

Nature Communications 13, 1--7 (2022)

Analogue cosmological particle creation in an ultracold quantum fluid of light

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Nonequilibrium Prethermal States in a Two-Dimensional Photon Fluid

Abuzarli, Murad and Cherroret, Nicolas and Bienaimé, Tom and Glorieux, Quentin

Phys. Rev. Lett. 129, 100602 (2022)

Nonequilibrium Prethermal States in a Two-Dimensional Photon Fluid

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Dissipative Phase Transition with Driving-Controlled Spatial Dimension and Diffusive Boundary Conditions

Li, Zejian and Claude, Ferdinand and Boulier, Thomas and Giacobino, Elisabeth and Glorieux, Quentin and Bramati, Alberto and Ciuti, Cristiano

Phys. Rev. Lett. 128, 093601 (2022)

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Quantitative Analysis of Shock Wave Dynamics in a Fluid of Light

Bienaimé, T. and Isoard, M. and Fontaine, Q. and Bramati, A. and Kamchatnov, A. M. and Glorieux, Q. and Pavloff, N.

Phys. Rev. Lett. 126, 183901 (2021)

Quantitative Analysis of Shock Wave Dynamics in a Fluid of Light

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Piekarski, Clara and Liu, Wei and Steinhauer, Jeff and Giacobino, Elisabeth and Bramati, Alberto and Glorieux, Quentin

Phys. Rev. Lett. 127, 023401 (2021)

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Blast Waves in a Paraxial Fluid of Light

Abuzarli, M. and Bienaimé, T. and Giacobino, E. and Bramati, A. and Glorieux, Q.

EPL (Europhysics Letters) 134, 24001 (2021)

Blast Waves in a Paraxial Fluid of Light

We study experimentally blast wave dynamics on a weakly interacting fluid of light. The fluid density and velocity are measured in 1D and 2D geometries. Using a state equation arising from the analogy between optical propagation in the paraxial approximation and the hydrodynamic Euler’s equation, we access the fluid hydrostatic and dynamic pressure. In the 2D configuration, we observe a negative differential hydrostatic pressure after the fast expansion of a localized over-density, which is a typical signature of a blast wave for compressible gases. Our experimental results are compared to the Friedlander waveform hydrodynamical model (Friedlander F. G., Proc. R. Soc. A: Math. Phys. Sci., 186 (1946) 322). Velocity measurements are presented in 1D and 2D configurations and compared to the local speed of sound, to identify the supersonic region of the fluid. Our findings show an unprecedented control over hydrodynamic quantities in a paraxial fluid of light.

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Polariton fluids for analogue gravity physics

Jacquet, M. J. and Boulier, T. and Claude, F. and Maître, A. and Cancellieri, E. and Adrados, C. and Amo, A. and Pigeon, S. and Glorieux, Q. and Bramati, A. and Giacobino, E.

Philosophical Transactions of the Royal Society A 378, 20190225 (2020)

Polariton fluids for analogue gravity physics

Analogue gravity enables the study of fields on curved space–times in the laboratory. There are numerous experimental platforms in which amplification at the event horizon or the ergoregion has been observed. Here, we demonstrate how optically generating a defect in a polariton microcavity enables the creation of one- and two-dimensional, transsonic fluid flows. We show that this highly tuneable method permits the creation of horizons. Furthermore, we present a rotating geometry akin to the water-wave bathtub vortex. These experiments usher in the possibility of observing stimulated as well as spontaneous amplification by the Hawking, Penrose and Zeld’ovich effects in fluids of light. This article is part of a discussion meeting issue ‘The next generation of analogue gravity experiments’.

Highly Photostable Perovskite Nanocubes: Toward Integrated Single Photon Sources Based on Tapered Nanofibers

Pierini, Stefano and D’Amato, Marianna and Goyal, Mayank and Glorieux, Quentin and Giacobino, Elisabeth and Lhuillier, Emmanuel and Couteau, Christophe and Bramati, Alberto

ACS Photonics 7, 2265-2272 (2020)

The interest in perovskite nanocrystals (NCs) such as CsPbBr3 for quantum applications is rapidly raising, as it has been demonstrated that they can behave as very efficient single photon emitters. The main problem to tackle in this context is their photostability under optical excitation. In this article, we present a full analysis of the optical and quantum properties of highly efficient perovskite nanocubes synthesized with an established method, which is used for the first time to produce quantum emitters and is shown to ensure increased photostability. These emitters exhibit reduced blinking together with a strong photon antibunching. Remarkably these features are hardly affected by the increase of the excitation intensity well above the emission saturation levels. Finally, we achieve for the first time the coupling of a single perovskite nanocube with a tapered optical nanofiber in order to aim for a compact integrated single photon source for future applications.

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Dark-Soliton Molecules in an Exciton-Polariton Superfluid

Maître, Anne and Lerario, Giovanni and Medeiros, Adria and Claude, Ferdinand and Glorieux, Quentin and Giacobino, Elisabeth and Pigeon, Simon and Bramati, Alberto

Phys. Rev. X 10, 041028 (2020)

Dark-Soliton Molecules in an Exciton-Polariton Superfluid

The general theory of dark solitons relies on repulsive interactions and, therefore, predicts the impossibility to form dark-soliton bound states. One important exception to this prediction is the observation of bound solitons in nonlocal nonlinear media. Here, we report that exciton-polariton superfluids can also sustain dark-soliton molecules, although the interactions are fully local. With a novel all-optical technique, we create two dark solitons that bind together to form an unconventional dark-soliton molecule. We demonstrate that the stability of this structure and the separation distance between two dark solitons is tightly connected to the driven-dissipative nature of the polariton fluid.

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Vortex-Stream Generation and Enhanced Propagation in a Polariton Superfluid

Lerario, Giovanni and Maître, Anne and Boddeda, Rajiv and Glorieux, Quentin and Giacobino, Elisabeth and Pigeon, Simon and Bramati, Alberto

Physical Review Research 2, 023049 (2020)

Vortex-Stream Generation and Enhanced Propagation in a Polariton Superfluid

In this work we implement an experimental configuration which exploits the specific properties of the optical bistability exhibited by the polariton system and we demonstrate the generation of a superfluid turbulent flow in the wake of a potential barrier. The propagation and direction of the turbulent flow are sustained by a support beam on distances an order of magnitude longer than previously reported. This technique is a powerful tool for the controlled generation and propagation of quantum turbulence and paves the way for the study of the hydrodynamics of quantum turbulence in driven-dissipative two-dimensional polariton systems.

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Microcavity Polaritons for Quantum Simulation

Boulier, Thomas and Jacquet, Maxime J. and Maître, Anne and Lerario, Giovanni and Claude, Ferdinand and Pigeon, Simon and Glorieux, Quentin and Amo, Alberto and Bloch, Jacqueline and Bramati, Alberto and Giacobino, Elisabeth

Advanced Quantum Technologies 3, 2000052 (2020)

Microcavity Polaritons for Quantum Simulation

Abstract Quantum simulations are one of the pillars of quantum technologies. These simulations provide insight in fields as varied as high energy physics, many-body physics, or cosmology to name only a few. Several platforms, ranging from ultracold-atoms to superconducting circuits through trapped ions have been proposed as quantum simulators. This article reviews recent developments in another well established platform for quantum simulations: polaritons in semiconductor microcavities. These quasiparticles obey a nonlinear Schrödigner equation (NLSE), and their propagation in the medium can be understood in terms of quantum hydrodynamics. As such, they are considered as “fluids of light.” The challenge of quantum simulations is the engineering of configurations in which the potential energy and the nonlinear interactions in the NLSE can be controlled. Here, some landmark experiments with polaritons in microcavities are revisited, how the various properties of these systems may be used in quantum simulations is discussed, and the richness of polariton systems to explore nonequilibrium physics is highlighted.

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Parallel dark-soliton pair in a bistable two-dimensional exciton-polariton superfluid

Lerario, G. and Koniakhin, S. V. and Maître, A. and Solnyshkov, D. and Zilio, A. and Glorieux, Q. and Malpuech, G. and Giacobino, E. and Pigeon, S. and Bramati, A.

Phys. Rev. Research 2, 042041 (2020)

Parallel dark-soliton pair in a bistable two-dimensional exciton-polariton superfluid

Collective excitations, such as vortex-antivortex and dark solitons, are among the most fascinating effects of macroscopic quantum states. However, two-dimensional (2D) dark solitons are unstable and collapse into vortices due to snake instabilities. Making use of the optical bistability in exciton-polariton microcavities, we demonstrate that a pair of dark solitons can be formed in the wake of an obstacle in a polariton flow resonantly supported by a homogeneous laser beam. Unlike the purely dissipative case where the solitons are gray and spatially separate, here the two solitons are fully dark, rapidly align at a specific separation distance, and propagate parallel as long as the flow is in the bistable regime. Remarkably, the use of this regime allows us to relax the phase fixing constraints imposed by the resonant pumping and to circumvent the polariton decay. Our work opens very wide possibilities for studying new classes of phase-density defects which can form in driven-dissipative quantum fluids of light.

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Revues de l’American Physical Society: La Qualité Pour Un Juste Prix!

Henri, Agnès and Knoop, Martina and Rousseau, Francoise and Bouju, Xavier and Daillant, Jean and Glorieux, Quentin and Langlais, Catherine and Duraud, JP and van Tiggelen, Bart and Jerome, Denis

Reflets de la Physique , (2020)

Revues de l’American Physical Society: La Qualité Pour Un Juste Prix!

Interferences between Bogoliubov excitations in superfluids of light

Fontaine, Quentin and Larré, Pierre-Élie and Lerario, Giovanni and Bienaimé, Tom and Pigeon, Simon and Faccio, Daniele and Carusotto, Iacopo and Giacobino, Élisabeth and Bramati, Alberto and Glorieux, Quentin

Phys. Rev. Research 2, 043297 (2020)

Interferences between Bogoliubov excitations in superfluids of light

Paraxial fluids of light represent an alternative platform to atomic Bose-Einstein condensates and superfluid liquids for the study of the quantum behavior of collective excitations. A key step in this direction is the precise characterization of the Bogoliubov dispersion relation, as recently shown in two experiments. However, the predicted interferences between the phonon excitations that would be a clear signature of the collective superfluid behavior have not been observed to date. Here, by analytically, numerically, and experimentally exploring the phonon phase velocity, we observe the presence of interferences between counterpropagating Bogoliubov excitations and demonstrate their critical impact on the measurement of the dispersion relation. These results are evidence of a key signature of light superfluidity and provide a characterization tool for quantum simulations with photons.

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Nanofiber Based Displacement Sensor

Ding, Chengjie and Joos, Maxime and Bach, Constanze and Bienaimé, Tom and Giacobino, Elisabeth and Wu, E and Bramati, Alberto and Glorieux, Quentin

Applied Physics B 126, 1--6 (2020)

Nanofiber Based Displacement Sensor

We report on the realization of a displacement sensor based on an optical nanofiber. A single gold nano-sphere is deposited on top of a nanofiber and the system is placed within a standing wave which serves as a position ruler. Scattered light collected within the guided mode of the fiber gives a direct measurement of the nanofiber displacement. We calibrated our device and found a sensitivity up to 1.2 nm/Hz—{\surd}. As an example of application, a mechanical model based on the Mie scattering theory is then used to evaluate the optically induced force on the nanofiber by an external laser and its displacement. With our sensing system, we demonstrate that an external force of 1 pN applied at the nanofiber waist can be detected.

Taming the snake instabilities in a polariton superfluid

Ferdinand Claude and Sergei V. Koniakhin and Anne Ma\^itre and Simon Pigeon and Giovanni Lerario and Daniil D. Stupin and Quentin Glorieux and Elisabeth Giacobino and Dmitry Solnyshkov and Guillaume Malpuech and Alberto Bramati

Optica 7, 1660--1665 (2020)

Taming the snake instabilities in a polariton superfluid

The dark solitons observed in a large variety of nonlinear media are unstable against the modulational (snake) instabilities and can break in vortex streets. This behavior has been investigated in nonlinear optical crystals and ultra-cold atomic gases. However, a deep characterization of this phenomenon is still missing. In a resonantly pumped two-dimensional polariton superfluid, we use an all-optical imprinting technique together with the bistability of the polariton system to create dark solitons in confined channels. Due to the snake instabilities, the solitons are unstable and break into arrays of vortex streets whose dynamical evolution is frozen by the pump-induced confining potential, allowing their direct observation in our system. A deep quantitative study shows that the vortex street period is proportional to the quantum fluid healing length, in agreement with the theoretical predictions. Finally, the full control achieved on the soliton patterns is exploited to give proof of principle of an efficient, ultra-fast, analog, all-optical maze solving machine in this photonic platform.

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Photonic crystal nanobeam cavities with optical resonances around 800\&\#x2009;\&\#x2009;nm

I. Saber and R. Boddeda and F. Raineri and D. Sanchez and G. Beaudoin and I. Sagnes and Q. Glorieux and A. Bramati and J. A. Levenson and K. Bencheikh

J. Opt. Soc. Am. B 36, 1823--1828 (2019)

Photonic crystal nanobeam cavities with optical resonances around 800\&\#x2009;\&\#x2009;nm

We report on the design and the fabrication of 1D photonic crystal nanobeam cavities with optical resonances around 800\&\#x00A0;nm, compatible with rubidium, cesium, or argon atomic transitions. The cavities are made of indium gallium phosphide material, a III-V semi-conductor compound which has a large index of refraction (n\&\#x2243;3.3) favoring strong optical confinement and small mode volumes. Nanobeam cavities with inline and side coupling have been designed and fabricated, and quality factors up to 2\&\#x00D7;104 have been measured.

Generating strong anti-bunching by interfering nonclassical and classical states of light

Rajiv Boddeda and Quentin Glorieux and Alberto Bramati and Simon Pigeon

Journal of Physics B: Atomic, Molecular and Optical Physics 52, 215401 (2019)

Generating strong anti-bunching by interfering nonclassical and classical states of light

In quantum optics, the second-order correlation function g(2)(τ) characterizes the photon statistics of a state of light and can be used to distinguish between its classical or quantum nature. In this article, we study a simple setup which offers the possibility to generate quantum states of light with very small g(2)(0), a signature of strong anti-bunched light. This can be achieved by mixing on a beamsplitter a coherent state with a nonclassical state, such as a squeezed state, and even with a bunched state (g(2)(0) > 1) such as a Schrödinger cat state. We elucidate the interference mechanism generating such strong anti-bunching and relate it to the unconventional photon blockade. We also detail how this effect can be applied to detect weakly squeezed states of light.

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Imaging light scattered by a subwavelength nanofiber, from near field to far field

Vivien Loo and Guillaume Blanquer and Maxime Joos and Quentin Glorieux and Yannick De Wilde and Valentina Krachmalnicoff

Opt. Express 27, 350--357 (2019)

Imaging light scattered by a subwavelength nanofiber, from near field to far field

We present a direct experimental investigation of the optical field distribution around a suspended tapered optical nanofiber by means of a fluorescent scanning probe. Using a 100 nm diameter fluorescent bead as a probe of the field intensity, we study interferences made by a nanofiber (400 nm diameter) scattering a plane wave (568 nm wavelength). Our scanning fluorescence near-field microscope maps the optical field over 36 \&\#x003BC;m2, with \&\#x003BB;\&\#x0002F;5 resolution, from contact with the surface of the nanofiber to a few micrometers away. Comparison between experiments and Mie scattering theory allows us to precisely determine the emitter-nanofiber distance and experimental drifts.

Stationary Quantum Vortex Street in a Driven-Dissipative Quantum Fluid of Light

Koniakhin, S. V. and Bleu, O. and Stupin, D. D. and Pigeon, S. and Maitre, A. and Claude, F. and Lerario, G. and Glorieux, Q. and Bramati, A. and Solnyshkov, D. and Malpuech, G.

Phys. Rev. Lett. 123, 215301 (2019)

Stationary Quantum Vortex Street in a Driven-Dissipative Quantum Fluid of Light

We investigate the formation of a new class of density-phase defects in a resonantly driven 2D quantum fluid of light. The system bistability allows the formation of low-density regions containing density-phase singularities confined between high-density regions. We show that, in 1D channels, an odd (1 or 3) or even (2 or 4) number of dark solitons form parallel to the channel axis in order to accommodate the phase constraint induced by the pumps in the barriers. These soliton molecules are typically unstable and evolve toward stationary symmetric or antisymmetric arrays of vortex streets straightforwardly observable in cw experiments. The flexibility of this photonic platform allows implementing more complicated potentials such as mazelike channels, with the vortex streets connecting the entrances and thus solving the maze.

Complete polarization control for a nanofiber waveguide using the scattering properties

Maxime Joos and Alberto Bramati and Quentin Glorieux

Opt. Express 27, 18818--18830 (2019)

Complete polarization control for a nanofiber waveguide using the scattering properties

We report on a protocol to achieve full control of the polarization in a nanofiber. The protocol relies on monitoring the light scattered out from a nanofiber by means of two optical systems with 45\&\#x000B0; camera angle difference. We study the disturbance of the nanofiber refractive index on the radiation of embedded scatterers, and we propose an explanation for the observed reduced scattering contrast of the nanofiber. Thanks to this approach, we demonstrate an accuracy of the polarization control larger than 95%.

Attenuation-free non-diffracting Bessel beams

Quentin Fontaine and Huiqin Hu and Simon Pigeon and Tom Bienaimé and E Wu and Elisabeth Giacobino and Alberto Bramati and Quentin Glorieux

Opt. Express 27, 30067--30080 (2019)

Attenuation-free non-diffracting Bessel beams

We report on a versatile method to compensate the linear attenuation in a medium, independently of its microscopic origin. The method exploits diffraction-limited Bessel beams and tailored on-axis intensity profiles, which are generated using a phase-only spatial light modulator. This technique for compensating one of the most fundamental limiting processes in linear optics is shown to be efficient for a wide range of experimental conditions (modifying the refractive index and the attenuation coefficient). Finally, we explain how this method can be advantageously exploited in applications ranging from bio-imaging light sheet microscopy to quantum memories for future quantum communication networks.

Fabrication and characterization of optical nanofiber interferometer and resonator for the visible range

Chengjie Ding and Vivien Loo and Simon Pigeon and Romain Gautier and Maxime Joos and E Wu and Elisabeth Giacobino and Alberto Bramati and Quentin Glorieux

New Journal of Physics 21, 073060 (2019)

We report the fabrication and characterization of photonic structures using tapered optical nanofibers. Thanks to the extension of the evanescent electromagnetic field outside of the nanofiber two types of devices can be built: a ring interferometer and a knot resonator. We propose a general approach to predict the properties of these structures using the linear coupling theory. In addition, we describe a new source of birefringence due to the ovalization of a nanofiber under strong bending, known in mechanical engineering as the Brazier effect.

CdSe/CdS Dot-in-Rods Nanocrystals Fast Blinking Dynamics.

Manceau, M. and Vezzoli, S. and Glorieux, Q. and Giacobino, E. and Carbone, L. and De Vittorio, M. and Hermier, J.-P. and Bramati, A.

ChemPhysChem 19, 3288-3295 (2018)

CdSe/CdS Dot-in-Rods Nanocrystals Fast Blinking Dynamics.

Abstract Analyzing the autocorrelation function of the fluorescence intensity, we demonstrate that these nanoemitters are characterized by a short value of the mean duration of bright periods (ten to a few hundreds of microseconds). The comparison of the results obtained for samples with different geometries shows that not only the shell thickness is crucial but also the shape of the dot-in-rods. Increasing the shell aspect ratio results in shorter bright periods suggesting that surface traps impact the stability of the fluorescence intensity.

Polarization Control of Linear Dipole Radiation Using an Optical Nanofiber

Joos, Maxime and Ding, Chengjie and Loo, Vivien and Blanquer, Guillaume and Giacobino, Elisabeth and Bramati, Alberto and Krachmalnicoff, Valentina and Glorieux, Quentin

Phys. Rev. Applied 9, 064035 (2018)

Polarization Control of Linear Dipole Radiation Using an Optical Nanofiber

We experimentally demonstrate that a linear dipole is not restricted to emit linearly polarized light, provided that it is embedded in the appropriate nanophotonic environment. We observe emission of various elliptical polarizations by a linear dipole, including circularly polarized light, without the need for birefringent components. We further show that the emitted state of polarization can theoretically span the entire Poincaré sphere. The experimental demonstration is based on elongated gold nanoparticles (nanorods) deposited on an optical nanofiber and excited by a free-space laser beam. The light directly collected in the guided mode of the nanofiber is analyzed in regard to the azimuthal position and orientation of the nanorods, observed by means of scanning electron microscopy. We demonstrate a mapping between purely geometrical degrees of freedom of a light source and all polarization states that could open the way to alternative methods for polarization control of light sources at the nanoscale.

Observation of the Bogoliubov Dispersion in a Fluid of Light

Fontaine, Q. and Bienaimé, T. and Pigeon, S. and Giacobino, E. and Bramati, A. and Glorieux, Q.

Phys. Rev. Lett. 121, 183604 (2018)

Observation of the Bogoliubov Dispersion in a Fluid of Light

Quantum fluids of light are a photonic counterpart to atomic Bose gases and are attracting increasing interest for probing many-body physics quantum phenomena such as superfluidity. Two different configurations are commonly used: the confined geometry where a nonlinear material is fixed inside an optical cavity and the propagating geometry where the propagation direction plays the role of an effective time for the system. The observation of the dispersion relation for elementary excitations in a photon fluid has proved to be a difficult task in both configurations with few experimental realizations. Here, we propose and implement a general method for measuring the excitations spectrum in a fluid of light, based on a group velocity measurement. We observe a Bogoliubov-like dispersion with a speed of sound scaling as the square root of the fluid density. This Letter demonstrates that a nonlinear system based on an atomic vapor pumped near resonance is a versatile and highly tunable platform to study quantum fluids of light.

Coherent merging of counterpropagating exciton-polariton superfluids

Boulier, T. and Pigeon, S. and Cancellieri, E. and Robin, P. and Giacobino, E. and Glorieux, Q. and Bramati, A.

Phys. Rev. B 98, 024503 (2018)

Coherent merging of counterpropagating exciton-polariton superfluids

We report the formation of a macroscopic coherent state emerging from colliding polariton fluids. Four lasers with random relative phases, arranged in a square, pump resonantly a planar microcavity, creating four coherent polariton fluids propagating toward each other. When the density (interactions) increases, the four fluids synchronize and the topological excitations (vortex or soliton) disappear to form a single quantum superfluid.

Injection of Orbital Angular Momentum and Storage of Quantized Vortices in Polariton Superfluids

Boulier, T. and Cancellieri, E. and Sangouard, N. D. and Glorieux, Q. and Kavokin, A. V. and Whittaker, D. M. and Giacobino, E. and Bramati, A.

Phys. Rev. Lett. 116, 116402 (2016)

Injection of Orbital Angular Momentum and Storage of Quantized Vortices in Polariton Superfluids

We report the experimental investigation and theoretical modeling of a rotating polariton superfluid relying on an innovative method for the injection of angular momentum. This novel, multipump injection method uses four coherent lasers arranged in a square, resonantly creating four polariton populations propagating inwards. The control available over the direction of propagation of the superflows allows injecting a controllable nonquantized amount of optical angular momentum. When the density at the center is low enough to neglect polariton-polariton interactions, optical singularities, associated with an interference pattern, are visible in the phase. In the superfluid regime resulting from the strong nonlinear polariton-polariton interaction, the interference pattern disappears and only vortices with the same sign are persisting in the system. Remarkably, the number of vortices inside the superfluid region can be controlled by controlling the angular momentum injected by the pumps.

Localised Excitation of a Single Photon Source by a Nanowaveguide

Geng, Wei and Manceau, Mathieu and Rahbany, Nancy and Sallet, Vincent and De Vittorio, Massimo and Carbone, Luigi and Glorieux, Quentin and Bramati, Alberto and Couteau, Christophe

Scientific reports 6, 19721 (2016)

Localised Excitation of a Single Photon Source by a Nanowaveguide

Nowadays, integrated photonics is a key technology in quantum information processing (QIP) but achieving all-optical buses for quantum networks with efficient integration of single photon emitters remains a challenge. Photonic crystals and cavities are good candidates but do not tackle how to effectively address a nanoscale emitter. Using a nanowire nanowaveguide, we realise an hybrid nanodevice which locally excites a single photon source (SPS). The nanowire acts as a passive or active sub-wavelength waveguide to excite the quantum emitter. Our results show that localised excitation of a SPS is possible and is compared with free-space excitation. Our proof of principle experiment presents an absolute addressing efficiency {\eta}a\,\textasciitilde\,10-4 only \textasciitilde 50\% lower than the one using free-space optics. This important step demonstrates that sufficient guided light in a nanowaveguide made of a semiconductor nanowire is achievable to excite a single photon source. We accomplish a hybrid system offering great potentials for electrically driven SPSs and efficient single photon collection and detection, opening the way for optimum absorption/emission of nanoscale emitters. We also discuss how to improve the addressing efficiency of a dipolar nanoscale emitter with our system.

Lattices of Quantized Vortices in Polariton Superfluids

Boulier, Thomas and Cancellieri, Emiliano and Sangouard, Nicolas D and Hivet, Romain and Glorieux, Quentin and Giacobino, Élisabeth and Bramati, Alberto

Comptes Rendus Physique 17, 893--907 (2016)

Lattices of Quantized Vortices in Polariton Superfluids

In this review, we will focus on the description of the recent studies conducted in the quest for the observation of lattices of quantized vortices in resonantly injected polariton superfluids. In particular, we will show how the implementation of optical traps for polaritons allows for the realization of vortex\textendash antivortex lattices in confined geometries and how the development of a flexible method to inject a controlled orbital angular momentum (OAM) in such systems results in the observation of patterns of same-sign vortices.

Exciton Fine Structure of CdSe/CdS Nanocrystals Determined by Polarization Microscopy at Room Temperature

Vezzoli, Stefano and Manceau, Mathieu and Leménager, Godefroy and Glorieux, Quentin and Giacobino, Elisabeth and Carbone, Luigi and De Vittorio, Massimo and Bramati, Alberto

ACS Nano 9, 7992-8003 (2015)

We present a method that allows determining the band-edge exciton fine structure of CdSe/CdS dot-in-rods samples based on single particle polarization measurements at room temperature. We model the measured emission polarization of such single particles considering the fine structure properties, the dielectric effect induced by the anisotropic shell, and the measurement configuration. We use this method to characterize the band-edge exciton fine structure splitting of various samples of dot-in-rods. We show that, when the diameter of the CdSe core increases, a transition from a spherical like band-edge exciton symmetry to a rod-like band edge exciton symmetry occurs. This explains the often reported large emission polarization of such particles compared to spherical CdSe/CdS emitters.

Vortex Chain in a Resonantly Pumped Polariton Superfluid

Boulier, T and Ter\c cas, H and Solnyshkov, DD and Glorieux, Q and Giacobino, E and Malpuech, G and Bramati, A

Scientific reports 5, 9230 (2015)

Vortex Chain in a Resonantly Pumped Polariton Superfluid

Exciton-polaritons are light-matter mixed states interacting via their exciton fraction. They can be excited, manipulated and detected using all the versatile techniques of modern optics. An exciton-polariton gas is therefore a unique platform to study out-of-equilibrium interacting quantum fluids. In this work, we report the formation of a ring-shaped array of same sign vortices after injection of angular momentum in a polariton superfluid. The angular momentum is injected by a l = 8 Laguerre-Gauss beam. In the linear regime, a spiral interference pattern containing phase defects is visible. In the nonlinear (superfluid) regime, the interference disappears and eight vortices appear, minimizing the energy while conserving the quantized angular momentum. The radial position of the vortices evolves in the region between the two pumps as a function of the density. Hydrodynamic instabilities resulting in the spontaneous nucleation of vortex-antivortex pairs when the system size is sufficiently large confirm that the vortices are not constrained by interference when nonlinearities dominate the system.

Advanced quantum noise correlations

Ulrich Vogl and Ryan T Glasser and Jeremy B Clark and Quentin Glorieux and Tian Li and Neil V Corzo and Paul D Lett

New Journal of Physics 16, 013011 (2014)

Advanced quantum noise correlations

We use the quantum correlations of twin beams of light to investigate the fundamental addition of noise when one of the beams propagates through a fast-light medium based on phase-insensitive gain. The experiment is based on two successive four-wave mixing processes in rubidium vapor, which allow for the generation of bright two-mode-squeezed twin beams followed by a controlled advancement while maintaining the shared quantum correlations between the beams. The demonstrated effect allows the study of irreversible decoherence in a medium exhibiting anomalous dispersion, and for the first time shows the advancement of a bright nonclassical state of light. The advancement and corresponding degradation of the quantum correlations are found to be operating near the fundamental quantum limit imposed by using a phase-insensitive amplifier.

Effect of charging on CdSe/CdS dot-in-rods single-photon emission

Manceau, M. and Vezzoli, S. and Glorieux, Q. and Pisanello, F. and Giacobino, E. and Carbone, L. and De Vittorio, M. and Bramati, A.

Phys. Rev. B 90, 035311 (2014)

Effect of charging on CdSe/CdS dot-in-rods single-photon emission

The photon statistics of CdSe/CdS dot-in-rods nanocrystals is studied with a method involving postselection of the photon detection events based on the photoluminescence count rate. We show that flickering between two states needs to be taken into account to interpret the single-photon emission properties. With postselection we are able to identify two emitting states: the exciton and the charged exciton (trion), characterized by different lifetimes and different second-order correlation functions. Measurements of the second-order autocorrelation function at zero delay with postselection shows a degradation of the single-photon emission for CdSe/CdS dot-in-rods in a charged state that we explain by deriving the neutral and charged biexciton quantum yields.

Quantum Mutual Information of an Entangled State Propagating through a Fast-Light Medium

Clark, Jeremy B and Glasser, Ryan T and Glorieux, Quentin and Vogl, Ulrich and Li, Tian and Jones, Kevin M and Lett, Paul D

Nature Photonics 8, 515 (2014)

Quantum Mutual Information of an Entangled State Propagating through a Fast-Light Medium

It is widely accepted that information cannot travel faster than c, the speed of light in vacuum. Here, we investigate the behaviour of quantum correlations and information in the presence of dispersion. To do so we send one half of an entangled state of light through a gain-assisted slow- or fast-light medium and detect the transmitted quantum correlations and quantum mutual information. We show that quantum correlations can be advanced by a small fraction of the correlation time, even in the presence of noise added by phase-insensitive gain. Additionally, although the peak of the quantum mutual information between the modes can be advanced, we find that the degradation of the mutual information due to added noise appears to prevent an advancement of the leading edge. In contrast, we demonstrate a significant delay of both the leading and trailing edges of the mutual information in a slow-light system.

An ultra-high optical depth cold atomic ensemble for quantum memories

B M Sparkes and J Bernu and M Hosseini and J Geng and Q Glorieux and P A Altin and P K Lam and N P Robins and B C Buchler

Journal of Physics: Conference Series 467, 012009 (2013)

An ultra-high optical depth cold atomic ensemble for quantum memories

Quantum memories for light lie at the heart of long-distance provably-secure communication. Demand for a functioning quantum memory, with high efficiency and coherence times approaching a millisecond, is therefore at a premium. Here we report on work towards this goal, with the development of a 87Rb magneto-optical trap with a peak optical depth of 1000 for the D2 f = 2 → F′ = 3 transition using spatial and temporal dark spots. With this purpose-built cold atomic ensemble we implemented the gradient echo memory (GEM) scheme on the D1 line. Our data shows a memory efficiency of 80 ± 2% and coherence times up to 195 μs.

Experimental characterization of Gaussian quantum discord generated by four-wave mixing

Vogl, Ulrich and Glasser, Ryan T. and Glorieux, Quentin and Clark, Jeremy B. and Corzo, Neil V. and Lett, Paul D.

Phys. Rev. A 87, 010101 (2013)

Experimental characterization of Gaussian quantum discord generated by four-wave mixing

We experimentally determine the Gaussian quantum discord present in two-mode squeezed vacuum generated by a four-wave mixing process in hot rubidium vapor. The frequency spectra of the discord as well as the quantum and classical mutual information are also measured. In addition, the effects of symmetric attenuation introduced into both modes of the squeezed vacuum on the Gaussian quantum discord, and the quantum mutual information and the classical correlations are examined experimentally. Finally, we show that due to the multi-spatial-mode nature of the four-wave mixing process, the Gaussian quantum discord may exhibit sub- or superadditivity depending on which spatial channels are selected.

Spatially addressable readout and erasure of an image in a gradient echo memory

Jeremy B Clark and Quentin Glorieux and Paul D Lett

New Journal of Physics 15, 035005 (2013)

Spatially addressable readout and erasure of an image in a gradient echo memory

We show that portions of an image written into a gradient echo memory can be individually retrieved or erased on demand, an important step toward processing a spatially multiplexed quantum signal. Targeted retrieval is achieved by locally addressing the transverse plane of the storage medium, a warm 85Rb vapor, with a far-detuned control beam. Spatially addressable erasure is similarly implemented by imaging a bright beam tuned near the 85Rb D1 line in order to scatter photons and induce decoherence. Under our experimental conditions atomic diffusion is shown to impose an upper bound on the effective spatial capacity of the memory. The decoherence induced by the optical eraser is characterized and modeled as the response of a two-level atom in the presence of a strong driving field.

Rotation of the noise ellipse for squeezed vacuum light generated via four-wave mixing

Corzo, Neil V. and Glorieux, Quentin and Marino, Alberto M. and Clark, Jeremy B. and Glasser, Ryan T. and Lett, Paul D.

Phys. Rev. A 88, 043836 (2013)

Rotation of the noise ellipse for squeezed vacuum light generated via four-wave mixing

We report the generation of a squeezed vacuum state of light whose noise ellipse rotates as a function of the detection frequency. The squeezed state is generated via a four-wave mixing process in a vapor of85Rb. We observe that rotation varies with experimental parameters such as pump power and laser detunings. We use a theoretical model based on the Heisenberg-Langevin formalism to describe this effect. Our model can be used to investigate the parameter space and potentially to tailor the ellipse rotation in order to obtain an optimum squeezing angle, for example, for coupling to an interferometer whose optimal noise quadrature varies with frequency.

Gradient echo memory in an ultra-high optical depth cold atomic ensemble

New Journal of Physics 15, 085027 (2013)

Gradient echo memory in an ultra-high optical depth cold atomic ensemble

Quantum memories are an integral component of quantum repeaters—devices that will allow the extension of quantum key distribution to communication ranges beyond that permissible by passive transmission. A quantum memory for this application needs to be highly efficient and have coherence times approaching a millisecond. Here we report on work towards this goal, with the development of a 87Rb magneto-optical trap with a peak optical depth of 1000 for the D2 F = 2 → F′ = 3 transition using spatial and temporal dark spots. With this purpose-built cold atomic ensemble we implemented the gradient echo memory (GEM) scheme on the D1 line. Our data shows a memory efficiency of 80 ± 2% and coherence times up to 195 μs, which is a factor of four greater than previous GEM experiments implemented in warm vapour cells.

Temporally multiplexed storage of images in a gradient echo memory

Quentin Glorieux and Jeremy B. Clark and Alberto M. Marino and Zhifan Zhou and Paul D. Lett

Opt. Express 20, 12350--12358 (2012)

Temporally multiplexed storage of images in a gradient echo memory

We study the storage and retrieval of images in a hot atomic vapor using the gradient echo memory protocol. We demonstrate that this technique allows for the storage of multiple spatial modes. We study both spatial and temporal multiplexing by storing a sequence of two different images in the atomic vapor. The effect of atomic diffusion on the spatial resolution is discussed and characterized experimentally. For short storage time a normalized spatial cross-correlation between a retrieved image and its input of 88 \% is reported.

Imaging using quantum noise properties of light

Jeremy B. Clark and Zhifan Zhou and Quentin Glorieux and Alberto M. Marino and Paul D. Lett

Opt. Express 20, 17050--17058 (2012)

Imaging using quantum noise properties of light

We show that it is possible to estimate the shape of an object by measuring only the fluctuations of a probing field, allowing us to expose the object to a minimal light intensity. This scheme, based on noise measurements through homodyne detection, is useful in the regime where the number of photons is low enough that direct detection with a photodiode is difficult but high enough such that photon counting is not an option. We generate a few-photon state of multi-spatial-mode vacuum-squeezed twin beams using four-wave mixing and direct one of these twin fields through a binary intensity mask whose shape is to be imaged. Exploiting either the classical fluctuations in a single beam or quantum correlations between the twin beams, we demonstrate that under some conditions quantum correlations can provide an enhancement in sensitivity when estimating the shape of the object.

Generation of pulsed bipartite entanglement using four-wave mixing

Quentin Glorieux and Jeremy B Clark and Neil V Corzo and Paul D Lett

New Journal of Physics 14, 123024 (2012)

Generation of pulsed bipartite entanglement using four-wave mixing

Using four-wave mixing in a hot atomic vapor, we generate a pair of entangled twin beams in the microsecond pulsed regime near the D1 line of 85Rb, making it compatible with commonly used quantum memory techniques. The beams are generated in the bright and vacuum-squeezed regimes, requiring two separate methods of analysis, without and with local oscillators, respectively. We report a noise reduction of up to 3.8 ± 0.2 dB below the standard quantum limit in the pulsed regime and a level of entanglement that violates an Einstein–Podolsky–Rosen inequality.

Extracting Spatial Information from Noise Measurements of Multi-Spatial-Mode Quantum States

Marino, AM and Clark, JB and Glorieux, Q and Lett, PD

The European Physical Journal D 66, 288 (2012)

Extracting Spatial Information from Noise Measurements of Multi-Spatial-Mode Quantum States

We show that it is possible to use the spatial quantum correlations present in twin beams to extract information about the shape of a binary amplitude mask in the path of one of the beams. The scheme, based on noise measurements through homodyne detection, is useful in the regime where the number of photons is low enough that direct detection with a photodiode is difficult but high enough that photon counting is not an option. We find that under some conditions the use of quantum states of light leads to an enhancement of the sensitivity in the estimation of the shape of the mask over what can be achieved with a classical state with equivalent properties (mean photon flux and noise properties). In addition, we show that the level of enhancement that is obtained is a result of the quantum correlations and cannot be explained with only classical correlations.

Quantum correlations by four-wave mixing in an atomic vapor in a nonamplifying regime: Quantum beam splitter for photons

Glorieux, Quentin and Guidoni, Luca and Guibal, Samuel and Likforman, Jean-Pierre and Coudreau, Thomas

Phys. Rev. A 84, 053826 (2011)

We study the generation of intensity quantum correlations using four-wave mixing in a rubidium vapor. The absence of cavities in these experiments allows to deal with several spatial modes simultaneously. In the standard amplifying configuration, we measure relative intensity squeezing up to 9.2 dB below the standard quantum limit. We also theoretically identify and experimentally demonstrate an original regime where, despite no overall amplification, quantum correlations are generated. In this regime, a four-wave mixing setup can play the role of a photonic beam splitter with nonclassical properties, that is, a device that splits a coherent state input into two quantum-correlated beams.

Time-resolved detection of relative-intensity squeezed nanosecond pulses in an87Rb vapor

Imad H Agha and Christina Giarmatzi and Quentin Glorieux and Thomas Coudreau and Philippe Grangier and Gaetan Messin

New Journal of Physics 13, 043030 (2011)

Time-resolved detection of relative-intensity squeezed nanosecond pulses in an87Rb vapor

We present theoretical and experimental results on the generation and detection of pulsed, relative-intensity squeezed light in a hot 87Rb vapor. The intensity noise correlations between a pulsed probe beam and its conjugate, generated through nearly degenerate four-wave mixing in a double-lambda system, are studied numerically and measured experimentally via time-resolved balanced detection. We predict and observe approximately − 1 dB of time-resolved relative-intensity squeezing with 50 ns pulses at 1 MHz repetition rate. (− 1.34 dB corrected for loss).

Double-Lambda microscopic model for entangled light generation by four-wave mixing

Glorieux, Q. and Dubessy, R. and Guibal, S. and Guidoni, L. and Likforman, J.-P. and Coudreau, T. and Arimondo, E.

Phys. Rev. A 82, 033819 (2010)

Double-Lambda microscopic model for entangled light generation by four-wave mixing

Motivated by recent experiments, we study four-wave-mixing in an atomic double-Λ system driven by a far-detuned pump. Using the Heisenberg-Langevin formalism, and based on the microscopic properties of the medium, we calculate the classical and quantum properties of seed and conjugate beams beyond the linear amplifier approximation. A continuous-variable approach gives us access to relative-intensity noise spectra that can be directly compared with experiments. Restricting ourselves to the cold-atom regime, we predict the generation of quantum-correlated beams with a relative-intensity noise spectrum well below the standard quantum limit (down to −6 dB). Moreover, entanglement between seed and conjugate beams measured by an inseparability down to 0.25 is expected. This work opens the way to the generation of entangled beams by four-wave mixing in a cold-atom sample.

Strong quantum correlations in four wave mixing in 85Rb vapor

Quentin Glorieux and Luca Guidoni and Samuel Guibal and Jean-Pierre Likforman and Thomas Coudreau

Strong quantum correlations in four wave mixing in 85Rb vapor

We study quantum intensity correlations produced using four-wave mixing in a room-temperature rubidiumvapor cell. An extensive study of the effect of the various parameters allows us to observe very large amounts ofnon classical correlations.

Photoionisation Loading of Large {Sr}+ Ion Clouds with Ultrafast Pulses

Removille, Sébastien and Dubessy, Romain and Glorieux, Quentin and Guibal, Samuel and Coudreau, Thomas and Guidoni, Luca and Likforman, J-P

Applied Physics B: Lasers and Optics 97, 47--52 (2009)

Photoionisation Loading of Large {Sr}+ Ion Clouds with Ultrafast Pulses

This paper reports on the use of ultrafast pulses for photoionisation loading of singly-ionised strontium ions in a linear Paul trap. We take advantage of an autoionising resonance of Sr neutral atoms to form Sr+ by two-photon absorption of femtosecond pulses at a wavelength of 431 nm. We compare this technique to electron-bombardment ionisation and observe several advantages of photoionisation. It actually allows for the loading of a pure Sr+ ion cloud in a low radio-frequency voltage amplitude regime. In these conditions, up to 4\texttimes 104 laser-cooled Sr+ ions were trapped.

Trapping and cooling of Sr\mathplusions: strings and large clouds

S Removille and R Dubessy and B Dubost and Q Glorieux and T Coudreau and S Guibal and J-P Likforman and L Guidoni

Journal of Physics B: Atomic, Molecular and Optical Physics 42, 154014 (2009)

Trapping and cooling of Sr\mathplusions: strings and large clouds

This paper reports on trapping and laser cooling of singly ionized strontium ions in a linear Paul trap. We describe the loading technique based on two-photon absorption of femtosecond pulses at a wavelength of 431 nm and we compare this technique to electron-bombardment ionization. We perform Doppler cooling of the ions in the few-ions regime as well as in the case of large clouds. The analysis of the fluorescence spectra and direct imaging of the cloud allows us to identify the Coulomb-crystal regime. These experiments open the way to the use of a large cold trapped-ion cloud as a medium for quantum optics and quantum information experiments.