1 / 35

1. Laboratoire de Photonique et de Nanostructures - CNRS, Marcoussis, France

FEW-PHOTON OPTICAL NONLINEARITY IN A QUANTUM DOT-PILLAR CAVITY DEVICE. 1. Laboratoire de Photonique et de Nanostructures - CNRS, Marcoussis, France 2. Université Paris Diderot – Paris 7, France.

samueldaniels
Download Presentation

1. Laboratoire de Photonique et de Nanostructures - CNRS, Marcoussis, France

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. FEW-PHOTON OPTICAL NONLINEARITY IN A QUANTUM DOT-PILLAR CAVITY DEVICE 1. Laboratoire de Photonique et de Nanostructures - CNRS, Marcoussis, France 2. Université Paris Diderot – Paris 7, France V. Loo1, C. Arnold1, O. Gazzano1, A. Lemaître1,I. Sagnes1, O. Krebs1, P. Voisin, P. Senellart1 and L. Lanco1,2

  2. Quantum information: how can we make photons interact? or Interaction between indistinguishable photons Coalescence on a beamsplitter Interaction between nearly simultaneous photons A single-photon switch? Interaction between delayed photons A spin-photon interface?

  3. Quantum information: how can we make photons interact? or Interaction between indistinguishable photons Coalescence on a beamsplitter Ultrabright sources of indistinguishable photons:Gazzano et al, Nature Comm. 4, 1425 (2013) Interaction between nearly simultaneous photons A single-photon switch? Interaction between delayed photons A spin-photon interface?

  4. Quantum information: how can we make photons interact? or Interaction between indistinguishable photons Coalescence on a beamsplitter Ultrabright sources of indistinguishable photons:Gazzano et al, Nature Comm. 4, 1425 (2013) Interaction between nearly simultaneous photons A single-photon switch? Optical nonlinearity with few-photon pulses:Loo et al, PRL 109, 166806 (2012) Interaction between delayed photons A spin-photon interface?

  5. Quantum information: how can we make photons interact? or Interaction between indistinguishable photons Coalescence on a beamsplitter Ultrabright sources of indistinguishable photons:Gazzano et al, Nature Comm. 4, 1425 (2013) Interaction between nearly simultaneous photons A single-photon switch? Optical nonlinearity with few-photon pulses:Loo et al, PRL 109, 166806 (2012) Interaction between delayed photons A spin-photon interface? Work in progress…

  6. A quantum dot-cavity device InGaAs/GaAs quantum dot Bragg mirrors conduction Optical mode (~ 930nm) ~ 1,35 eV valence Controlled light-matter coupling Near-unity coupling/collection efficiencies Device challenges : Low optical losses Low QD dephasing

  7. A quantum dot-cavity device InGaAs/GaAs quantum dot Bragg mirrors conduction Optical mode (~ 930nm) ~ 1,35 eV valence Controlled light-matter coupling Near-unity coupling/collection efficiencies Device challenges : Low optical losses Low QD dephasing

  8. Deterministic coupling through in-situ lithography

  9. In-situ lithography: why? cavity mode QD micropillar Spatial matching : QD at the maximum of the field intensity Spectral matching : EQD = Emode

  10. Sample growth MBE Growth Aristide Lemaître

  11. Sample growth MBE Growth Aristide Lemaître Random locations + random transition energies E2 E3 E4 E1

  12. Sample growth Random micropillar: probability of success below 10-3 MBE Growth Aristide Lemaître

  13. Sample growth Positive photoresist MBE Growth Aristide Lemaître

  14. Spatial matching… 1340 1345 1350 1355 x y EQD Laserexcitation Photo-luminescence Selected QD transition PL Intensity (a.u.) E (meV) QD PL intensity accuracy 50nm y ( ) 15 12 9 6 3 0 x ( ) piezoelectric actuators

  15. Spatial matching… 1340 1345 1350 1355 x y EQD Laserexcitation Selected QD transition Photo-luminescence PL Intensity (a.u.) Insulation E (meV) QD PL intensity accuracy 50nm y ( ) 15 12 9 6 3 0 x ( ) piezoelectric actuators

  16. …and spectral matching 1340 1345 1350 1355 EX EM = 1355 1350 Mode Energy (meV) 1345 1340 0,5 1,0 2,0 1,5 radius (µm) x y EQD Laserexcitation Selected QD transition Photo-luminescence PL Intensity (a.u.) Insulation E (meV) 90s 60s 45s 30s 25s 20s 18s 16s Defining the appropriate radius EQD =EMODE piezoelectric actuators

  17. Deterministically coupled devices A. Dousse et al, PRL 101, 267404 (2008)

  18. Optical nonlinearity with few-photon pulses

  19. The 2-level system: a highly nonlinear medium Without a cavity: QD Efficiency = few % With a cavity: QD in excited state QD in ground state 1 1 Reflectivity Reflectivity 0 0 Photon energy Photon energy Transition: ~1 photon inside the cavity

  20. All-optical switching: recent results Photonic crystals Switch for ~ 1 photon insidethe cavity n Switch for a single incident photon? N N>100 with photonic crystals

  21. A cavity-QD device : figures of merit QD-cavity coupling strength: g QD dephasing rate: cavity damping rate: gdecay + g* gdecoh = k= k0+kloss 2

  22. A cavity-QD device : figures of merit Total damping Side leakage Mirror damping QD-cavity coupling strength: g QD dephasing rate: cavity damping rate: gdecay + g* gdecoh = k= k0+kloss 2 k0 hout = k0 + kloss Ideal: hout =1 Output-coupling efficiency

  23. A cavity-QD device : figures of merit Total damping Side leakage Mirror damping QD-cavity coupling strength: g QD dephasing rate: cavity damping rate: gdecay + + g* gdecoh = = k= k0+kloss 2 Total dephasing Lifetime-limited contribution Pure-dephasing contribution gdecohgdecay k0 hout = nc = k0 + kloss 4 g2 Ideal: Ideal: hout =1 nc << 1 Critical intracavity photon number Output-coupling efficiency

  24. Experimental setup Cryostat 4K-50K Tunable Laser (CW) hin Input-coupling efficiency Reference APD Measurement APD hin~1 achievable in micropillars Arnold et al, Applied Physics Letters 100, 111111 (2012) To begin with : CW measurements

  25. Reflectivity spectra (low-power) Temperature: T= 35.9 K Temperature: T= 34.8 K Unequal excitonic / photonic parts Equal excitonic / photonic parts 1.0 1.0 0.9 0.9 Reflectivity Reflectivity 0.8 0.8 0.7 0.7 1.3242 1.3240 1.3241 1.3242 1.3240 1.3241 Photon energy (eV) Photon energy (eV)

  26. Reflectivity map (experimental data) 1.0 44 cavity -like 42 0.9 40 38 Upper branch QD-like 0.8 Reflectivity Temperature (K) 36 QD-like 34 Lower branch 0.7 32 30 cavity-like 0.6 1.3242 1.3240 1.3241 Photon energy (eV)

  27. Giant optical nonlinearity – CW measurements n = 0.0026 n = 0.0003 n = 0.15 n = 0.02 n = 1.5 n = 7 P0=1.1 nW P0=3.4 nW Input coupling hin= 0.95 1.0 1.0 Reflectivity 0.8 0.8 0.6 0.6 1.324 1.3241 1.3242 1.324 1.3241 1.3242 Output coupling hout=0.16 P0=36 nW P0=11 nW 1.0 1.0 Reflectivity 0.8 0.8 0.6 0.6 1.324 1.3241 1.3242 1.324 1.3241 1.3242 Critical photon number : P0=110 nW P0=340 nW nc = 0.035 1.0 1.0 n<<nC : low-power limit Reflectivity 0.8 0.8 n>>nC : high-power limit 0.6 0.6 1.324 1.3241 1.3242 1.324 1.3241 1.3242 Photon energy (eV) What about N? Photon energy (eV)

  28. Pulsed measurements Ti:Sa laser N Cryostat single photon APD single photon APD Pulse width: 34 ps ~ 1/k Fixed wavelength Same beam shape Same input-coupling expected 1.0 hin= 0.95 Reflectivity 0.8 0.6 1.324 1.3241 1.3242

  29. Few-photon nonlinearity threshold 8 photons Fit with quantum master equation: hin= 0.95 hout= 0.16 0.90 V. Loo et al, PRL 109, 166806 (2012) 0.88 Nonlinear threshold: 8 incident photons / pulse 0.86 0.84 Factor 10 improvement Reflectivity 0.82 0.80 0.78 104 10-1 100 102 103 101 Incident photons per pulse N If hout ≈1: nonlinearity threshold at the single-photon level !

  30. Increasing the output-coupling The standard way: k0 hout = k0 + kloss Less mirror pairs: → higherk0 Larger diameter: → lowerkloss But decreased light-matter coupling…

  31. Increasing the output-coupling The smart way: adiabatic cavities The standard way: k0 hout = k0 + kloss Adiabatic Standard Less mirror pairs: → higherk0 mirror cavity mirror Larger diameter: → lowerkloss Lermer et al. PRL 108, 057402 (2012) Towards nonlinearity at the single-photon level… …but deterministic single-photon switching ?

  32. Beyond the two-level system « The maximal success probability for a single-photon router is 60% with a two-level system » Barak Dayan, OASIS conference, Tel-Aviv, February 19th 2013 Nonlinearity in photonic molecules Theory: Bamba et al, PRA 83, 021802(R) (2011) LPN: entangled photons with photonic molecules Dousse et al. Nature 466, 217-220 (2010)

  33. Beyond the two-level system « The maximal success probability for a single-photon router is 60% with a two-level system » Barak Dayan, OASIS conference, Tel-Aviv, February 19th 2013 4-level system: spin in charged QDs Nonlinearity in photonic molecules Theory: Bamba et al, PRA 83, 021802(R) (2011) LPN: entangled photons with photonic molecules s- s+ Dousse et al. Nature 466, 217-220 (2010) ~ 1 µs coherence delayed photons!

  34. Further perspectives New in-situ processes for electrical control Spin-photon entanglement Theory: Hu et al, PRB 78, 085307 (2008) Logic gates with quantum light sources Real-time monitoring of single events 1.0 RL 0.9 Reflectivity 0.8 RE 0.7 0.6 0 200 400 600 Time (µs)

  35. Many thanks to: Vivien Loo Christophe Arnold Pascale Senellart Aristide Lemaître Isabelle Sagnes Olivier Gazzano Olivier Krebs Paul Voisin JCJC MIND, P3N DELIGHT, P3N CAFE SSQN QD-CQED

More Related