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Emulating analog gravity with cavity polaritons

Emulating analog gravity with cavity polaritons. H . S. Nguyen E. Galopin , A. Lemaître , L. Le Gratiet , I . Sagnes , A . Amo. J. B loch. Now Assistant Professor Lyon, France. Palaiseau France. P. Grisins I . Carusotto. D. Sanvitto.

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Emulating analog gravity with cavity polaritons

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  1. Emulating analog gravity with cavity polaritons H. S. Nguyen E. Galopin, A. Lemaître, L. Le Gratiet, I. Sagnes, A. Amo J. Bloch Now Assistant Professor Lyon, France Palaiseau France P. Grisins I. Carusotto D. Sanvitto D. Gerace Lecce Pavia Trento

  2. Emulating analog gravity with cavity polaritons Nguyen et al. PRL 114, 036402 (2015)

  3. Microcavitypolaritons Angle θ(º) AlGaAs Mirror kin-plane Photon Quantum wells Cavity Emission energy (eV) Emissionenergy(eV) c Mirror kin-plane(μm-1) Optical cavity Bragg mirror GaAs/AlAs Cavity Bragg mirror GaAs/AlAs TEM, G. Patriarche, LPN

  4. Upper polariton Lower polariton Microcavity polaritons Angle θ(º) T = 5 K AlGaAs Mirror kin-plane Photon Quantum wells Cavity Emissionenergy(eV) Exciton ~ 15meV Mirror Microcavity polaritons : mixed exciton-photon states kin-plane(μm-1) Properties Photonic component Small effective mass, large group velocity Optical excitation, detection • Interactions -χ(3) (dominated by exchange) Excitonic component

  5. 1 0 10 mm Interferometry Coherenceg(1) g(2) Density Probing polariton states Imaging of k-space q k// = w/c sin(q) Imaging of real space - vortices - solitons

  6. Polariton interactions: superfluidity Resonantexcitation Non-linear Schrödinger equation LPB CW Pump CW Pump pol-pol interaction decay potential Carusotto, Ciuti, Rev. Mod. Phys. 85, 299 (2013) Seealso: Bolda, et al., PRL 86, 416 (2001),Chiao, et al., PRA 60, 4114 (1999)

  7. Superfluidity: theory Non-linear Schrödinger equation Resonantexcitation LPB CW Pump pol-pol interaction decay CW Pump potential High power High power Lowpower lowmomentum highmomentum cs cs vf < cs vf> cs E E kp E 0 0 0 k k k FLOW Superfluid Supersonic Elasticscattering Carusotto and Ciuti, PRL 93, 166401 (2004)

  8. Nearfield CCD (d) Farfield CCD kz k Y q k║ X Excitation laser Microcavity Superfluidity: experiment Resonantexcitation Structuraldefect as a probe LPB CW Pump High power High power Lowpower lowmomentum highmomentum cs cs vf < cs vf> cs E E kp E 0 0 0 k k k FLOW 30 µm Superfluid Supersonic Elasticscattering Amo et al., Nat, Phys.5, 805 (2009) See also: Kohnle et al., PRL 106, 255302 (2011)

  9. Subsonic-supersonic transition engineered obstacle V < c V < c V > c Solnyshkovet al PRB84, 233405 (2011) Gerace and CarusottoPRB 86, 144505 (2012) EnhancedHawking temperature (TH ~ 1-15 K)

  10. Polaritonin 1D cavities Polaritonlateralconfinement Electron beamlithography + ion dry etching 20 µm 1D polaritonsub-bands Quantizationof kx: kx= np/w n=1,2,3,… ky (µm-1)

  11. Subsonic-supersonic transition Resonant excitation E0 1 µm 1.3 µm 3 µm Lowdensity High density Higher transmission Ekin ~ 0.5 meV V(x) x 0.85 meV DOWNSTREAM V > c UPSTREAM V < c Nguyen et al. PRL 114, 036402 (2015)

  12. Subsonic-supersonic transition Measurements in real-space: High density in the Upstream Lowdensity in the Upstream p = 7 mW p = 100 mW Defect position Defect position Simulation Simulation • Interference pattern in the Upstream • Existence of a back scattering flow • Not superfluid Suppression of back scattering in the Upstream  Superfluid/Subsonic !

  13. Momentum space 7 mW UPSTREAM reflection 80 mW Energy Scattered Fluid k reflection 100 mW subsonic Energy Fluid k

  14. Momentum space 7 mW UPSTREAM reflection 80 mW Flow speed reflection Speed of sound 100 mW subsonic

  15. An acoustic black hole for polaritons Nguyen et al. PRL 114, 036402 (2015)

  16. Conclusions and prospects Realization an acoustic black hole for polariton Nguyen et al. PRL 114, 036402 (2015) Measure of spatial correlations? PjotrsGrišins et al., Phys. Rev. B 94, 144518 (2016) Recati, N. Pavloff, and I. Carusotto, Phys. Rev. A 80, 043603 (2009)

  17. Conclusions and prospects Tilted Dirac cones in 2D materialsemulate black holemetric G. E. Volovik and K. Zhang, JETP Lett. 104, 645 (2016) H. Huang et al., Phys. Rev. B 98, 121110 (2018)

  18. Polaritonhoneycomblattice Graphène Pillardiameter=3µm Interpillar distance a=2.4µm 4mm Energy(meV – 1577) Dirac cones Jacqminet al., PRL 112, 116402 (2014) See also Yamamot (Stanford), Krizhanovskii (Sheffield)

  19. Uniaxialstrain in polaritongraphene: tilted and type III Dirac cones COMPRESSION EXPANSION M. Milicevic et al., to appear in PRX (Arxiv1807.08650)

  20. Acoustic black holes Sonic Horizon Supersonic:V(x) > c(x) Subsonic: V(x) < c(x) Sonic black hole V(x) Sound waves emitted in the supersonicregion cannot propagate to the subsonic region, as light cannot escape from the black hole Fluid speed c(x) Sound speed (courtesy S. Robertson)

  21. Hydrodynamic blackhole analogues Cosmological blackhole Hydrodynamic analogue cs : speed of sound c : speed of light Event Horizon W. G. Unruh, PRL 46, 1351 (1981), PRD 51 2827 (1995) “The propagation of sound waves in accelerating fluids is formally equivalent to light waves in the proximity of a black hole event horizon.” Studying Hawking radiation in hydrodynamicanalogues • It is possible to demonstratethat the scalarfield of the velocity (i.e. ) isdescribed by the Euler-Lagrange equation of a metric:

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