Laboratoire Charles Coulomb UMR 5221 CNRS/UM2 (L2C)


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Polariton condensates in polariton waveguides : quantum fluids of light for integrated photonics

par Christelle EVE - publié le

Master 2 / PhD Thesis Project Polariton condensates in polariton waveguides : quantum fluids of light for integrated photonics

The interaction between electronic excitations (excitons) and photons is strongly enhanced in optical microcavities, compared to a bulk medium. When the interaction is large enough, it can reach the strong coupling regime. In this regime, the new eigenstates are the so-called polaritons, half exciton/half photon quasi-particles. They can be generated, transported, accumulated in dense quantum phases and brought into strong interactions. The discovery of the Bose condensation of polaritons in 2006 [1] has triggered many interesting research projects dedicated to the exploration of these “quantum fluids of light”, and to the development of polaritonic devices.
GaN and ZnO-based microcavities have raised a large interest in the community thanks to their robust excitons and large oscillator strength. Indeed polariton condensates can be demonstrated at room temperature, which is a striking advantage with respect to GaAs devices operated at cryogenic temperatures. Together with our colleagues from the laboratories CRHEA, C2N and IP, our group has demonstrated in 2013 the condensation of polaritons in a ZnO microcavity at 300K [2,3].
The present proposal for a Master Internship and a possible continuation as a PhD is focused on a new kind of polaritonic device : the polaritonic waveguide, i.e. an optical waveguide in which propagating photons and excitons are in the strong coupling regime. The waveguide polaritons have much longer lifetimes than cavity polaritons due to the low waveguide losses, and their investigation in GaAs [4], GaN [5] and ZnO [6] is quite recent. We have demonstrated very recently that polariton lasing can be achieved in this new geometry, with the formation of new polariton condensates.
We plan to investigate the continuous and pulsed regime for the laser emission, based on the formation of light solitons. The student would possibly participate in the fabrication of new samples at the C2N clean room facility. The project stands at the frontier between non-linear optics, quantum optics and condensed matter physics.

- Kasprzak, J. et al. Bose-Einstein condensation of exciton polaritons. Nature 443, 409–414 (2006).

- Li, F. et al. From Excitonic to Photonic Polariton Condensate in a ZnO-Based Microcavity. Phys Rev Lett 110, 196406– (2013).

- propagation of polariton condensates in a ZnO microcavity. Phys. Rev. B 92, 235308 (2015).

- Walker, P. M. et al. Ultra-low-power hybrid light–matter solitons. Nat. Commun. 6, 8317 (2015).

- Ciers, J. et al., Propagating Polaritons in III-Nitride Slab Waveguides, Phys. Rev. Applied, 7, 034019 (2017) 6. Jamadi, O. et al., Edge-emitting polariton laser and amplifier based on a ZnO waveguide, Light : Science & Applications, 7, 82 (2018)

Contacts :
Thierry Guillet
Christelle Brimont