# INTERNSHIP : Impact of multiple non-linear mechanisms on quantum states of light generation

# INTERNSHIP : Impact of multiple non-linear mechanisms on quantum states of light generation

We aim at identifying how multiple non-linear mechanisms impact the generation of non-classical state of light, such as squeezed states [1].

Non-linear interactions are necessary to generate quantum states of light. Through such interaction, mediated by non-linear optical matter, a set of photons are converted. The quantum nature of the resulting light derived directly from this conversion. For example, optical parametrical amplificator (a four-wave mixing process) produces a correlated pair of beams (signal and idler) from a strongly pumped one [2,3]. But non-linear optical devices encompass more than a single desired non-linear mechanisms. Many competing processes take place simultaneously in these devices coupling many modes together. If in principle, all these processes can lead to non-classical states of light their competition may in contrary leads to a reduction of the quantum nature of the light produced. In a recent work, it was shown that disorder in the non-linear optical devices can lead to a reduction of the weight of unwanted non-linear process and so protect the quantum nature of the state of light generated [4].

The project will start with a simplistic model where only a single non-linear process is present, for which we will quantify the non-classical nature: the squeezing. Then we will complexity the model introducing more modes and more non-linear mechanisms.

[1] D. Walls, ”Squeezed states of light,”*Nature*

**306**, 141 (1983). [2] M. D. Reid and P. D. Drummond, ”Quantum Correlations of Phase in Nondegenerate Parametric Oscillation,”

*Physical Review Letters*

**60**, 2731 (1988). [3] C. W. Gardiner and P. Zoller, “

*Quantum Noise*“, 3rd ed, Springer Berlin 2004. [4] M. Bamba, S. Pigeon, and C. Ciuti, ”Quantum Squeezing Generation versus Photon Localization in a Disordered Planar Microcavity,”

*Physical Review Letters*

**104**, 213604 (2010).

Interested candidates should contact Simon Pigeon (simon.pigeon@lkb.upmc.fr)

Theoretical internship.

Duration: 3 to 6 months.