Fluids of light in complex environments

Fluids of light in complex environments

Stage de M2

Fluids of light in complex environments

General context

Quantum fluids of light is a rapidly growing research field merging many-body physics and nonlinear optics. Connecting light propagation in nonlinear media and quantum hydrodynamics [1] allows to perform quantum simulations of systems of very different nature, ranging from astrophysics to condensed matter. One of the most outstanding evidence of light behaving as an interacting fluid is its ability to carry itself as a superfluid. Among others, a biased photorefractive crystal is a perfectly adapted platform for the study of fluids of light allowing to i) range from a non-interacting to a repulsive/attractive interacting system and ii) design an customed spatial structuring of the refractive index map. This latter is achieved by photo-inducing local non-permanent modifications of the refractive index of the material [2]. At the Institut de Physique de Nice, we developed a state-of-the-art experimental set-up and recently reported a direct experimental detection of the transition to superfluidity in the flow of a fluid of light past an obstacle in a bulk nonlinear crystal [3]. One challenging continuation of this work, in the framework of waves in complex media, consists in investigating experimentally the interplay between superfluidity and localisation effects.


The objective is to increase the level of complexity of the 2D potential and examine its influence on the superfluid behaviour of light. We will focus on the interplay between localisation effects (non- superfluid regime) and perfect transmission (superfluid regime); two contrasting phenomena which occur in the following configurations.
We will first consider photon fluids in disordered potentials. While the non-interacting regime can lead to spatial localisation [4], a repulsive interaction tends to suppress this effect. A transition should then occur in favor of superfluidity, which will be the first objective of the study.
As an opening, we will focus on a crystalline arrangement that allows topological phase transitions [5]. In the linear regime, robust light states get localized. How such a robustness is affected by interactions is an opened question.
Addressing these fondamental issues from the photon fluid and many-body physics points of view will allow to consider light transport in nonlinear complex, and especially disordered, media from a novel perspective.

[1] I. Carusotto and C. Cuiti, “Quantum fluids of light”, Rev. Mod. Phys. 85, 299 (2013).
[2] O. Boughdad et al, “Anisotropic nonlinear refractive index measurement of a photorefractive crystal via spatial self-phase modulation”, To be published in Opt. Exp. (2019), arXiv:1907.09865.
[3] C. Michel et al, “Superfluid motion and drag-force cancellation in a fluid of light”, Nat. Commun. 9, 2108 (2018).
[4] Schwartz et al., “Transport and Anderson localization in disordered 2D photonic lattices”, Nature 446, 52 (2007).
[5] Lu et al., “Topological photonics”, Nature Photon. 8, 821 (2014).


We are looking for candidates with an outstanding academic record coupled with a broad outlook and a strong interest in both quantum hydrodynamics and non-linear optics, from the experimental and/or numerical point of view. The Institut de Physique de Nice largely contributed to the field at both experimental and numerical levels. Thus the candidate will have the opportunity to closely work with experts the Institute is used to collaborate with.
The candidate will have the opportunity to apply to the Doctoral School for Fundamental and Applied Science (EDSFA) for a PhD thesis on this topic. The internship gratification is about 450 e net/month.


If you are interested, or for any question or information about the internship, please contact :
Claire Michel : claire.michel@inphyni.cnrs.fr, +33 (0) 4 89 15 28 56
Matthieu Bellec : mathieu.bellec@inphyni.cnrs.fr, +33 (0) 4 89 15 28 16

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