UNconventional Integrated quantum nanophotonic sources From spontaneous sYmmetry breaking

Project Information

UNIFY

Grant agreement ID: 841351

DOI

10.3030/841351

Project closed

EC signature date 24 July 2019

Start date 1 September 2019

End date 31 August 2021

Funded under

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Total cost

€ 184 707,84

EU contribution

€ 184 707,84

Coordinated by

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE CNRS
France

Periodic Reporting for period 1 - UNIFY (UNconventional Integrated quantum nanophotonic sources From spontaneous sYmmetry breaking)

Reporting period: 2019-09-01 to 2021-08-31

Summary of the context and overall objectives of the project

UNIFY targets innovative semiconductor quantum nanosources based on state-of-the art hybrid technology of III-V semiconductors on Silicon. The main goal of UNIFY is to demonstrate quantum correlations with III-V semiconductor nanocavity devices operating at room temperature. This would represent a breakthrough in integrated quantum photonics since state-of-the-art single photon sources are based on deterministic coupling of single photon emitters to optical cavities, with stringent conditions for their spectral & spatial alignment inducing complex fabrication technology and low temperature operation.
Our project relies on unconventional approaches to generate strong quantum correlations using nonlinear coupled optical cavities. In particular, the realization of efficient single photon sources depends on the ability to produce strong photon antibunching, i.e. to generate one photon at a time thus suppressing multi-photon states.
Integrated quantum photonic sources based on nanocavities in III-V semiconductors: We have proposed two alternative solutions to state-of-the-art quantum sources in integrated photonics. A first approach, called « passive devices », aimed to generate quantum correlations using coupled nonlinear optical cavities. This « passive » approach aimed at demonstrating a recent theoretical result: entangled states have been predicted in the vicinity of symmetry breaking phase transitions –called pitchfork bifurcations– in a resonant excitation regime. From the experimental point of view, this involved implementing, in the passive regime, the pitchfork bifurcation already observed in the active regime (nanolaser).
A second approach consisted of using « active devices », i.e. light emitters, such as coupled nanolasers. This more exploratory task aimed at investigating photon correlations between the hybrid modes of photonic molecules. These studies required nanolasers operating in the low photon number regime which, in photonic crystal nanolasers, can be achieved through mode engineering to obtain high spontaneous emission factor devices.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We have obtained two important scientific results: i) the main one has been obtained in the passive excitation regime, where we have experimentally demonstrated the spontaneous mirror symmetry breaking in two coupled nonlinear nanocavities in 2D InP-based membranes under coherent resonant excitation. This paves the way for future entanglement measurements in the photons emitted by the cavities. ii) On the « active device» side, we have provided a direct observation of a lasing zero mode –a photonic version of Majorana excitations– in a three coupled cavity system, a promising approach that would potentially enable non-Abelian statistics for fault tolerant quantum computation.
Each of these two results is submitted for publications:
- B. Garbin, A. Giraldo, K. J. H. Peters, N. G. R. Broderick, A. Spakman, F. Raineri, A. Levenson, S. R. K. Rodriguez, B. Krauskopf, and A. M. Yacomotti, "Spontaneous symmetry breaking in a coherently driven nanophotonic bose-hubbard dimer," arXiv :2108.01655 2021. (under review)
- F. Hentinger, M. Hedir, B. Garbin, M. Marconi, L. Ge, F. Raineri, A. Levenson, and A. M. Yacomotti, “Direct observation of zero modes in a non-hermitian nanocavity array,” arXiv :2108.09672 2021. (under review)
They have also been presented in several conferences, including an invited oral presentation at CLEO/Europe-EQEC 2021 in Munich (online), Germany.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Although quantum correlations have been elusive throughout this project, we have produced the basic results of UNIFY: the demonstration of spontaneous symmetry breaking in the passive (resonant excitation) regime of a photonic dimer.
Importantly, the main UNIFY result –SSB under coherent excitation– undoubtably ensured the researcher’s exposure to the scientific community, which was the main impact sought by this project. This is demonstrated by two main recent indicators: the invited talk B. Garbin has given at CLEO/Europe-EQEC 2021 (ranked 2 out of more than 100 submissions), and a manuscript that is now successfully overcoming the first reviewing stage in Physical Review Letters. More generally, as anticipated by the proposal, B. Garbin became a specialist in active nanophotonics, trained in few photon nonlinearities, thus significantly enlarging his domain of expertise, enhancing the researcher profile on the nanophotonic side and strengthening independence and decision-making skills. As a result, B. Garbin become a brilliant independent researcher with a vast knowhow in experimental nonlinear optics, nanophotonics and nonlinear dynamics.

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