UNIFY · UNconventional Integrated quantum nanophotonic sources From spontaneous sYmmetry breaking

UNconventional Integrated quantum nanophotonic sources From spontaneous sYmmetry breaking

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.

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