Phase-resolved imaging of confined exciton-polariton wave functions in elliptical traps

Nardin, Gaël; Léger, Yoan; Piętka, B.; Morier‐Genoud, F.; Deveaud-Plédran, Benoît

doi:10.1103/physrevb.82.045304

Cited by 36 publications

(28 citation statements)

References 28 publications

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“…5(a) and 6(a). Adopting the numerical analysis of off-axis filtering by keeping the interference components and removing the plane wave components [28], we are able to extract the underlying real-space phase distribution presented in Figs . Except the phase polarity choice, which does not carry any physical meaning since the relative phase difference between the lobes matters, the experimental phase maps confirm that the coherent states at nonzero points carry f -orbital symmetry in both lattice devices.…”

Section: F-orbital Symmetry Of Point Condensationmentioning

confidence: 99%

f-band condensates in exciton-polariton lattice systems

et al. 2014

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We report the condensation of microcavity exciton-polaritons at points located on the boundary between the third and higher Brillouin zones in hexagonal lattices: triangular and honeycomb geometries. We collect experimental evidence that supports the finite momentum condensation: (1) the coherent Bragg peaks formed at nonzero points; (2) the nonlinear intensity increase in the exciton-polariton emission at quantum degeneracy threshold; (3) the spectral linewidth behavior: narrowing near threshold and broadening above threshold; and (4) the equivalent 4f y 3 −3x 2 y -like orbital symmetry in real space. The f -orbital state at points appears as a metastable momentum valley to trap exciton-polaritons, which is explained by single-particle band-structure calculations.

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Section: F-orbital Symmetry Of Point Condensationmentioning

confidence: 99%

f-band condensates in exciton-polariton lattice systems

et al. 2014

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“…The error bars take into account the standard deviation of the linear fit, as well as a systematic error coming from the determination of the phase gradient induced by the set-up alignment (see ref. 40 for how this reference phase gradient can be determined). The value of the local sound velocity is determined from the density map, originally in arbitrary units, which needs to be scaled to the blue-shift ng .…”

Section: Methodsmentioning

confidence: 99%

“…The circularly polarized laser pulse is spectrally filtered to form a 1 meV broad, 3 ps long pulse, which is then split into one excitation pulse and one reference pulse. The reference pulse is directed through a telescope for spatial filtering and wavefront tuning, and incident at a slight angle on the CCD, to serve as a phase reference 40 . The excitation pulse is passed through a delay line and focused on the back of the sample using a 25 cm focal length camera objective, providing a Fourier limited 25 µm diameter excitation spot.…”

Section: Methodsmentioning

confidence: 99%

Hydrodynamic nucleation of quantized vortex pairs in a polariton quantum fluid

et al. 2011

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Quantized vortices appear in quantum gases at the breakdown of superfluidity. In liquid helium and cold atomic gases, they have been indentified as the quantum counterpart of turbulence in classical fluids. In the solid state, composite light-matter bosons known as exciton polaritons have enabled studies of non-equilibrium quantum gases and superfluidity. However, there has been no experimental evidence of hydrodynamic nucleation of polariton vortices so far. Here we report the experimental study of a polariton fluid flowing past an obstacle and the observation of nucleation of quantized vortex pairs in the wake of the obstacle. We image the nucleation mechanism and track the motion of the vortices along the flow. The nucleation conditions are established in terms of local fluid density and velocity measured on the obstacle perimeter. The experimental results are successfully reproduced by numerical simulations based on the resolution of the Gross-Pitaevskii equation.H ydrodynamic instabilities in classical fluids were studied in the pioneering experiments of Bénard in the 1910's. Convective Bénard-Rayleigh flows and Bénard-Von Kár-mán streets are now well known examples in nonlinear and chaos sciences 1 . In conventional fluids, the flow around an obstacle is characterized by the dimensionless Reynolds number Re = vR/ν, with v and ν the fluid velocity and dynamical viscosity, respectively, and R the diameter of the obstacle. When increasing the Reynolds number, laminar flow, stationary vortices, Bénard-Von Kármán streets of moving vortices and fully turbulent regimes are successively observed in the wake of the obstacle 1 .In quantum fluids, such as liquid helium or atomic BoseEinstein condensates, quantum turbulence has long been predicted to appear at the breakdown of superfluidity 2-8 . In superfluid systems, the Reynolds number cannot be defined owing to the absence of viscosity. However, quantum turbulence, in the form of quantized vortices, appears simultaneously with dissipation and drag on the obstacle once a critical velocity is exceeded. This critical velocity is predicted to be lower than the Landau criterion for superfluidity far from the obstacle, because of a local increase of the fluid velocity in the vicinity of the impenetrable obstacle 2,4,5 .Experimental evidence has been given for the appearance of a drag force or heat above some critical velocity in superfluid helium 5 and atomic Bose-Einstein condensates 9,10 . In stirred atomic gases, vortex lattices appear above a critical stirring frequency 11-13 , analogously to the rotating bucket experiments originally performed with superfluid helium 14 . Irregular vortex tangle patterns were also observed under an external oscillating perturbation, indicating the presence of turbulence in the atomic cloud 15 . Finally, vortex nucleation has been reported in the wake of a blue-detuned laser moving above a critical velocity through the condensate 16,17 . However, no experiment has yet allowed the imaging of the hydrodynamic nucleation mechanism with ...

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“…2, we have used a homodyne imaging setup. 13 Polariton states were excited from the back side of the sample (held in a cold-finger cryostat at a liquid helium temperature). The coherent emission of the polariton state was collected from the front side of the sample, and interfered on a CCD with a reference laser beam.…”

Section: Methodsmentioning

confidence: 99%

“…11,12 The generation of optical vortices strongly coupled to the excitonic resonance (or polariton vortices) has been demonstrated in a patterned microcavity. 13,14 The vortices, carrying an integer orbital angular momentum state, were the result of a coherent superposition of eigenmodes of an elliptic polariton trap, excited using a continuous wave (cw) laser. In the present work we are considering the case where the confined polariton states are not continuously driven by the laser frequency (like a forced oscillator), but are excited with a laser pulse and let free to evolve.…”

Section: Introductionmentioning

confidence: 99%

Coherent oscillations between orbital angular momentum polariton states in an elliptic resonator

et al. 2011

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Abstract. We optically excited the eigenmodes of an elliptic resonator in a semiconductor microcavity. Using a pulsed excitation, we created a superposition of eigenmodes, and imaged the temporal evolution of the coherent emission pattern. A semiconductor quantum well was embedded in the microcavity structure. The system was operated in the strong light matter coupling regime, where the eigenmodes are hybrid half-photonic half-excitonic quasiparticles called exciton polaritons. Oscillations between orbital angular momentum states (or vortex states) were observed, and turned out to be remarkably well described within the Poincaré sphere representation. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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Phase-resolved imaging of confined exciton-polariton wave functions in elliptical traps

Cited by 36 publications

References 28 publications

f-band condensates in exciton-polariton lattice systems

f-band condensates in exciton-polariton lattice systems

Hydrodynamic nucleation of quantized vortex pairs in a polariton quantum fluid

Coherent oscillations between orbital angular momentum polariton states in an elliptic resonator

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