Conference Agenda

Exciton-polaritons are hybrid light–matter quasiparticles that arise from the strong coupling between excitonic resonances and confined optical modes in microcavities. While foundational studies have primarily focused on GaAs-based heterostructures, the emergence of two-dimensional semiconductors—such as transition metal dichalcogenide (TMD) monolayers and layered perovskites—has opened new avenues for exploring polariton physics in novel material and photonic regimes.

This presentation focuses on the simultaneous enhancement of light–matter coupling and polariton nonlinearities by engineering both the electromagnetic environment and the excitonic properties of the active materials. Coupling efficiency and interaction strength are further improved through unconventional cavity designs that leverage phenomena such as surface optical modes and bound states in the continuum, as well as through material innovations like suspended monolayers and single-crystal layered perovskites.

The results establish 2D polariton systems as promising platforms for fundamental investigations in the strong and ultrastrong coupling regimes, as well as for the development of integrated photonic technologies for classical and quantum information processing.

We demonstrate a nonlinear AlGaAs photonic chip generating biphotons with high-dimensional spatial correlations. Photon pairs are generated by parametric down conversion in a waveguide array and simultaneously spread through quantum walks along the various waveguides, allowing to generate various types of high-dimensional entangled states of light. We further implement the Su-Schriefer-Heeger model and demonstrate the topological protection of the SPDC process against disorder. These results highlight nonlinear waveguide arrays as a promising platform for exploring the interplay between nonlinearity, disorder and topology in quantum photonic circuits.

Lithium niobate-on-insulator (LNOI) has emerged as a cornerstone for on-chip nonlinear optics, combining strong second-order nonlinearity with low-loss waveguides and nanofabrication compatibility. We demonstrate compact and efficient optical frequency converters built on a 4-inch LNOI wafer. Using an optimized process—integrating waveguide definition with post-etch domain inversion—we realize second-harmonic generation (SHG) with on-chip efficiency approaching 90%. This performance benefits from quasi-phase matching (QPM), tight optical confinement, and smooth waveguide sidewalls. Compared to traditional chip-scale approaches, our method offers improved manufacturability and consistency without compromising nonlinear efficiency. The devices are well suited for scalable integration in systems for frequency translation, amplification, and quantum light generation.

Bragg Scattering Four-Wave mixing (BS-FWM) is used in fibers to frequency shift single photons. The main limitation of this nonlinear process is the phase-matching requirement. In this work, we investigate how this condition can be controlled by changing the fiber temperature. We then are able to optimize the efficiency of the BS-FWM process for selected wavelengths. This tunability by temperature is beneficial for fiber-based actively multiplexed single photons sources : it is possible to generate photons and shift their frequency with the same fiber and wavelengths involved.

We contrast the self-organization of light in a nonlinear optical cavity against the recently introduced theory of self-organized bistability (SOB). This reveals that the nonlinear optical cavity may serve as a platform for the first experimental realization of SOB and drives further research into information processing in nonlinear optical cavities.