1. Guillaume TAREL, PhC Course, QD EMISSION 1 Control of spontaneous emission of QD using photonic crystals

2. Guillaume TAREL, PhC Course, QD EMISSION 2 Radiative transition -> Spontaneous emission All light sources except lasers + excited emitter environment

3. Guillaume TAREL, PhC Course, QD EMISSION 3 Excited emitter -> emission of a photon after a characteristic lifetime + excited emitter environment = Radiative transition -> Spontaneous emission All light sources except lasers 

4. Guillaume TAREL, PhC Course, QD EMISSION 4 A lot of interest in modifying spontaneous emission -Faster emission: Integrated photonics, high speed light sources - Single photon sources: Quantum optics, Quantum criptography - Better emission coupling factor 

5. Guillaume TAREL, PhC Course, QD EMISSION 5 Emitter : dimensionality of structures Baier M., PhD Thesis, 2005 Spatial Variations of band edge for carriers (e and h)

6. Nanopyramids of Gallium Arsenide Guillaume TAREL, PhC Course, QD EMISSION 6 Control Spontaneous emission (SE) Quantum dot: 3D confinment atomic like emitter Low extraction efficiency: Absorption+reflected part+ even total intern reflection Easy incorporation in devices

7. Guillaume TAREL, PhC Course, QD EMISSION 7 « By intentionnaly placing boundaries close to a radiative system, one realize new situations in which excited state decay can be either supressed, greatly enhanced, or even made reversible.» S. Haroche, 1990, Fundamental systems in Quantum Optics -> Cavity Quantum Electrodynamic Environment ? +

8. Guillaume TAREL, PhC Course, QD EMISSION 8 F. Krauss Science 20 May 2005: 1122-1123 Cavity decay rate > QD cavity coupling strength SE rate calculated from fermi golden rule… Weak coupling

9. Guillaume TAREL, PhC Course, QD EMISSION 9 -> on-resonance enhanced of resonance supressed See e.g. Andreani et Al., Physica status solidi. B. mode volumes and Q factor

10. Guillaume TAREL, PhC Course, QD EMISSION 10 Purcell effect -> Tailoring spontaneous emission E.M.Purcell Phys. Rev. 69 (1946) p. 681 Vahala, Nature 2003 Excited emitter -> emission of a photon after a characteristic lifetime Purcell effect reduces spontaneous emission lifetime Properties of the emitter modified but not fundamentally altered : weak coupling

11. Guillaume TAREL, PhC Course, QD EMISSION 11 Low dimensionality structures Photons confined by modulation of the refractive index: planar microcavity, photonic wires, micropillars, microdisks… Vahala, Nature 2003

12. Guillaume TAREL, PhC Course, QD EMISSION 12 Andreani et Al., Physica status solidi. B. Photonic crystals

13. Guillaume TAREL, PhC Course, QD EMISSION 13 QD+Photonic crystals Both electrons and photons are confined in all dimensions + +

14. Guillaume TAREL, PhC Course, QD EMISSION 14 Vahala Nature 424, 839-846 (2003) M0 and M1 cavitys Need small mode volumes High Q – Small V

15. Guillaume TAREL, PhC Course, QD EMISSION 15 Phys. Rev. Lett. 95, 013904 (2005) Strauf et Al., Phys. Rev. Lett. 96, 127404 (2006) Designs concepts holes position and size

16. Guillaume TAREL, PhC Course, QD EMISSION 16 Yoshie et al., Nature 432, 200-203

17. Guillaume TAREL, PhC Course, QD EMISSION 17 Andreani et Al., Physica status solidi. B.

18. Guillaume TAREL, PhC Course, QD EMISSION 18 Phys. Rev. Lett. 95, 013904 (2005) What is done: 1/ fabrication of structures : emitter embedded in photonic crystal 2/ try to find an emitter coupled to a cavity mode Spectral + Spatial positioning

19. Guillaume TAREL, PhC Course, QD EMISSION 19 Phys. Rev. B 71, 241304 (2005): Kress et al. H1 PC cavity Pronounced CQED effect First example r/a r: hole radius

20. Guillaume TAREL, PhC Course, QD EMISSION 20 Phys. Rev. B 71, 241304 (2005): Kress et al. H1 PC cavity Deeper shift in the bandgap First example

21. Guillaume TAREL, PhC Course, QD EMISSION 21 Phys. Rev. B 71, 241304 (2005): Kress et al. Shortening of emission lifetime of around 5.6 H1 PC cavity Maximum enhancement around 20 Max(photon lifetime) 2ps Typical QD SE time 1 ns

22. Guillaume TAREL, PhC Course, QD EMISSION 22 Phys. Rev. B 71, 241304 (2005): Kress et al. H1 PC cavity Shortening AND lengthening Unpaterned membrane

23. Guillaume TAREL, PhC Course, QD EMISSION 23 Phys. Rev. B 66, 041303 (2002): Happ et al. Hexagonal defect microcavity H2 (7 missing holes, triangular lattice, filling factor 40%) Ground state transition of the dots (170) Pump rate limited 4 of the defect modes of a H2 cavity High power no resolution of QD individual emission 2nd example

24. Guillaume TAREL, PhC Course, QD EMISSION 24 Phys. Rev. B 66, 041303 (2002): Happ et al. Hexagonal defect microcavity H2 Mode peaks emerge from the spectra Lifetime limited, difference off/on resonance

25. Guillaume TAREL, PhC Course, QD EMISSION 25 Phys. Rev. B 66, 041303 (2002): Happ et al. *9 SE rate enhancement due to purcell effect on/off resonance

26. Guillaume TAREL, PhC Course, QD EMISSION 26 Phys. Rev. Lett. 95, 013904 (2005) What is done: 1/ fabrication of structures : emitter embedded in photonic crystal 2/ try to find an emitter coupled spectraly and spatially to a cavity mode

27. Guillaume TAREL, PhC Course, QD EMISSION 27 One more step: « deterministic coupling» Light-matter coupling is no more due to chance Badolato et al., Science 20 May 2005: 1158 - 1161

28. Guillaume TAREL, PhC Course, QD EMISSION 28 Writing of the S1 PhC Trace of the stacked QDs Electric field intensity from FDTD calculations -> high Q cavity mode resonance QD transition energy BUT remains red shifted = approximate SPECTRAL COUPLING Positionning of the QD SPATIAL COUPLING

29. Guillaume TAREL, PhC Course, QD EMISSION 29 Spectral tuning of the mode resonance 3 etching cycles 5 etching cycles QD emission intensity is modified Enhancement of radiative decay rate of around 5 Enlarge PC holes and thin PC membrane

30. Guillaume TAREL, PhC Course, QD EMISSION 30 Strong coupling Other really interesting aspects : Cavity decay rate < QD cavity coupling strength Vahala, Nature 2003 Cavity decay rate > QD cavity coupling strength = Purcell effect Modify spontaneous emission CONCLUSION Photonic crystals = tailoring of spontaneous emission using Purcell effect