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Superfluidity of Polaritons in Engineered Potentials in Semiconductor Microcavities

Learn about superfluidity in semiconductor microcavities and the experimental observations, potential landscape engineering, and quantum fluid effects.

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Superfluidity of Polaritons in Engineered Potentials in Semiconductor Microcavities

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  1. Superfluidity of Polaritons in Engineered Potentials in Semiconductor Microcavities Alberto Amo, C. Adrados, J. Lefrère, E. Giacobino, A. Bramati Laboratoire Kastler Brossel, UPMC, ENS, CNRS, Paris, FR S. Pigeon, C. Ciuti Laboratoire MPQ, Université Denis Diderot, CNRS, Paris, FR I. Carusotto BEC-CNR-INFM and Dipartimento di Fisica, Universita di Trento, Povo, IT R. Houdré Institut de Physique de la Matière Condensée, EPFL, Lausanne CH

  2. Outline Polaritons in semiconductor microcavities Observation of superfluidity of polaritons Engineering the polariton landscape

  3. Semiconductor microcavities Angle θ(º) θ GaAs Upper polariton kin-plane Photon Emission energy(eV) Exciton ~ 5meV Top DBR Quantum Wells Lower polariton Bottom DBR kin-plane(μm-1) Polaritons

  4. Semiconductor microcavities Angle θ(º) θ GaAs Upper polariton kin-plane Photon Emission energy(eV) Exciton ~ 5meV Top DBR Quantum Wells Lower polariton Bottom DBR kin-plane(μm-1) Polaritons Properties Composite bosons Excitonic component strong interactions (non-linearities 3) Photonic component low mass (10-5 me) Short lifetime (~ps) out of equilibrium

  5. Polariton condensation Excitation m/me Tc lT at Tc Atomic BEC 104 <1 mK 1 mm Emission energy(eV) 10-5 20-300 K 1-10 mm Polariton condensate Lower polariton kin-plane(μm-1) Polariton density T = 5 K CdTe ky kx Kasprzak et al. Nature, 443, 409 (2006)

  6. Polariton quantum fluid effects Quantized vortices (m=1) Interferogram Phase map Lagoudakis et al., Nature Phys.4, 706 (2008) Imprinted vortices (m=1,2)and persistent currents Sanvitto et al., Nature Phys.DOI: 10.1038/NPHYS1668 (2010)

  7. Polariton quantum fluid effects Quantized vortices (m=1) Fluid dynamics Interferogram Phase map Real space Lagoudakis et al., Nature Phys.4, 706 (2008) Momentum space Imprinted vortices (m=1,2)and persistent currents Amo et al., Nature457, 291 (2009) Sanvitto et al., Nature Phys.DOI: 10.1038/NPHYS1668 (2010)

  8. Landau criteriom for superfluidity Interacting Boson condensate linearized spectrum of excitations E cs k

  9. Landau criteriom for superfluidity Interacting Boson condensate linearized spectrum of excitations SUPERFLUID E E Galilean boost cs+vf cs FLOW cs-vf vf < cs k k

  10. Landau criteriom for superfluidity Interacting Boson condensate linearized spectrum of excitations SUPERFLUID E E Galilean boost cs+vf cs FLOW cs-vf vf < cs k k ČERENKOV REGIME E E Galilean boost cs+vf cs FLOW cs-vf vf > cs k k I. Carusotto and C. Ciuti, phys. stat. sol. (b)242, 2224 (2005)

  11. Polariton superfluidity Resonantly excited condensate with low momentum Elastic scattering E - Ep Pump ky (mm-1) Linear regime Realspace FLOW 30 µm Momentumspace Polariton density

  12. Polariton superfluidity Resonantly excited condensate with low momentum Elastic scattering Collapse of the ring E - Ep E - Ep Pump vf < cs Pump ky (mm-1) ky (mm-1) 1 Linear regime Superfluid Realspace FLOW 30 µm 0 Momentumspace Polariton density Amo et al., Nature Phys.5, 805 (2009)

  13. Polariton superfluidity Resonantly excited condensate with low momentum Elastic scattering Collapse of the ring E - Ep E - Ep Pump vf < cs Pump ky (mm-1) ky (mm-1) 1 Linear regime Superfluid Realspace FLOW 30 µm 0 Gross-Pitaevskiisimulations FLOW 30 µm Polariton density Amo et al., Nature Phys.5, 805 (2009)

  14. Superfluid regime

  15. Čerenkov regime (supersonic) High momentum Elastic scattering Linear wavefronts vf > cs E - Ep E - Ep Pump supersonic ky (mm-1) ky (mm-1) 1 Linear regime Čerenkov Realspace FLOW 40 µm 0 Gross-Pitaevskiisimulations FLOW 40 µm Polariton density Amo et al., Nature Phys.5, 805 (2009)

  16. Supersonic atomic BEC q Carusotto et al.PRL97,260403 (2006) Čerenkov regime (supersonic) High momentum Elastic scattering Linear wavefronts vf > cs E - Ep E - Ep Pump supersonic ky (mm-1) ky (mm-1) 1 Linear regime Čerenkov Realspace FLOW 40 µm 0 Gross-Pitaevskiisimulations FLOW 40 µm Polariton density Amo et al., Nature Phys.5, 805 (2009)

  17. Polariton landscape engineering probe σ+ FLOW 20 μm Defect-free area

  18. Polariton landscape engineering polariton-polariton interaction probe σ+ control σ- + FLOW 20 μm 20 μm Strong field:renormalization of the polariton energy Defect-free area control Polariton energy y

  19. Polariton landscape engineering polariton-polariton interaction probe σ+ control σ- probe σ++control σ- detection σ+ + = FLOW FLOW 20 μm 20 μm Strong field:renormalization of the polariton energy Defect-free area control Polariton energy y Amo et al., arXiv:1003.0131v1

  20. Polariton landscape engineering Probe + Probe + Probe only horizontal control diagonal control No control scattered injected injected injected 30 μm scattered Amo et al., arXiv:1003.0131v1

  21. Polariton landscape engineering Probe + Probe + Probe only horizontal control diagonal control No control scattered injected injected injected 30 μm scattered Amo et al., arXiv:1003.0131v1

  22. Polariton landscape engineering SUPERFLUID REGIME(high probe power) Probe + Probe + Probe only horizontal control diagonal control No control scattered injected injected injected injected 30 μm no scattering scattered Amo et al., arXiv:1003.0131v1

  23. Summary Observation of superfluidity of polaritons Supersonic regime access to the sound speed Polariton-polariton interactions landscape engineering polariton circuits localization effects Josephson oscillations

  24. Near field CCD (a) (d) Far field CCD kz k Y q k║ X Excitation laser Microcavity sample Single polariton fluid: set-up Single laser excitation (CW, single mode) resonant excitation of one polariton mode Excitation close to the bottom of the lower polariton branch UPB LPB Transmission experiment CW Pump

  25. Other situations SUPERFLUID AROUND SEVERAL DEFECTS FLOW 40 µm SHADOW EFFECT AROUND BIG DEFECT FLOW 40 µm Polariton density

  26. Superfluidity checklist Nature 457, 273 (2009) Resonantly pumped polariton condensates Amo, Lefrère, et al., Nature Physics, (in press). I Carusotto talk at ICSCE 4 conference (Cambridge, UK, 2008), available athttp://www.tcm.phy.cam.ac.uk/BIG/icsce4/talks/carusotto.pdf

  27. Y X Polariton fluid dynamics: set up sample Lens F Fourier plane 2ps pulsed fA Microcavity sample (grown at LPN) IDLER Lens Areal space imaging CW PUMP Energy selection imaging spectrometer Lens Bmomentum space imaging l/2 cavity20 nm GaAs QW Streak Camera CCD ħΩRabi= 4.4 meV ky kx

  28. Polariton landscape engineering polariton-polariton interaction probe σ+ control σ- probe σ++control σ- detection σ+ + = FLOW FLOW 20 μm 20 μm Strong field:renormalization of the polariton energy Defect-free area Simulation GP control FLOW Polariton energy y Amo et al., arXiv:1003.0131v1

  29. Polariton landscape engineering polariton-polariton interaction probe σ+ control σ- probe σ++control σ- detection σ+ + = FLOW FLOW 20 μm 20 μm Strong field:renormalization of the polariton energy Defect-free area Real defect control FLOW Polariton energy 30 µm y Amo et al., arXiv:1003.0131v1

  30. Polariton fluid dynamics Original streak camera set-up v = 1.2 mm/ps (~1% light speed) Study of the dynamics of polariton wavepackets t = 7 ps t = 28 ps t = 48 ps 20 μm Division in two in the presence of a big defect t = 8 ps t = 25 ps t = 45 ps 20 μm Amo et al., Nature457, 291 (2009)

  31. UPB LPB TOPO Idler CW Pump TOPO Signal TOPO Coexistence of three fluids • Steady state CW (pump) 100 mm spot • Triggered OPO (signal) 16 mm spot • fed by pump • Idler Pulse Pump polaritons Energy Signal polaritons Amo et al., Nature457, 291 (2009)

  32. Linear dispersion pol-pol interaction normal mode coupling decay CW Pump Pulsed probe 1 DE 0 Amo et al., Nature457, 291 (2009)

  33. t= 28ps t= 48ps t= 7ps a b Coherent propagation Amo et al., Nature457, 291 (2009)

  34. Flow through a defect I t= 13ps t= 8ps t= 36ps t= 50ps a b 2.5 0.0 Amo et al., Nature457, 291 (2009)

  35. Frictionless flow E=ħpump Pump polaritons • Pump fluid: scattering waves • Signal fluid • no scattering with the defect Peaked momentum E=ħsignal Signal polaritons compatible with superfluid behaviour kX kY K-space real space Amo et al., Nature457, 291 (2009)

  36. Noise studies in the superfluid regime Intensity noise polariton density statistics Noise decreases in the superfluid regime Superfluid threshold

  37. Splitting in two II t = 25 ps t = 8 ps t = 45 ps a b Amo et al., Nature457, 291 (2009)

  38. FLOW FLOW FLOW 40 µm 30 µm 30 µm Polariton superfluidity T = 5 K High density (quantum fluid regime) Low density Linear regime Superfluid Čerenkov vf<cs vf >cs Scattering with defects Fluid without friction Linear wavefronts Amo et al., Nature Physics 5, 805 (2009)

  39. FLOW FLOW FLOW 40 µm 30 µm 30 µm Polariton superfluidity High density (quantum fluid regime) T = 5 K Low density Linear regime Superfluid Čerenkov vf<cs vf >cs Scattering with defects Fluid without friction Linear wavefronts Amo et al., Nature Physics 5, 805 (2009)

  40. Čerenkov regime (supersonic) High momentum Elastic scattering Linear wavefronts vf > cs E - Ep E - Ep Pump supersonic ky (mm-1) ky (mm-1) 1 Linear regime Čerenkov Realspace FLOW 40 µm 0 Gross-Pitaevskiisimulations FLOW 40 µm Polariton density Amo et al., Nature Phys.5, 805 (2009)

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