Observation of photon droplets with orbital angular momentum and their dynamics
July 20th, 2018 KALI WILSON Heriot-Watt University, UK

Systems with competing attractive and repulsive interactions have a tendency to form droplets. This balancing act occurs in systems as varied as water, liquid helium and ultra-cold atomic gases. I will present experimental evidence of photon droplets formed when a monochromatic laser beam propagates through an attractive (focusing) nonlocal nonlinear medium. Photon droplets are self-bound, finite-sized states of light that are robust to size and shape perturbations due to a balance of competing attractive and repulsive forces. It has recently been shown theoretically, via a multipole expansion of the nonlocal nonlinearity, that the self-bound state arises due to competition between the s-wave and d-wave nonlinear terms, together with diffraction. The theoretical photon droplet framework encompasses both a soliton-like stationary ground state and the non-soliton-like dynamics that ensue when the system is driven into an excited state. I will present experiments and complementary numerics supporting the existence of these photon droplet states, and measurements of the dynamical evolution of the photon droplet orbital angular momentum.

Seminar, July 20st ,2018, 12:00. Seminar Room

Hosted by Prof. Leticia Tarruell