Nonlinear spatiotemporal light bullets: origin and stability
The NOSTER project is about unveiling the dynamics and features of spatiotemporal coherent structures emerging in multimode optical fibers, such as spatiotemporal solitons, also known as light bullets.  Solitons are particle-like states, emerging due to a double balance between linear and nonlinear processes, that maintain their shape while propagating in a medium. Solitons arise in a large variety of different natural media, ranging from hydrodynamics and plasma physics, to nonlinear optics and biology. In nonlinear optics, the emergence of solitons is related to the light confinement in time or space.  One basic example of a system yielding to this type of state are single mode optical fibers, where the Kerr nonlinearity counteracts the spreading of the light produced by the chromatic dispersion. In multimode optical fibers, temporal and spatial effects, such as chromatic dispersion and diffraction, can occur simultaneously and counteract the Kerr nonlinearity, leading to the space-time confinement of light, and therefore, to the formation of much more complex coherent structures. My approach in this project is to predict and analyze the generation of localized spatiotemporal states, in particular light bullets and vortices, from a pattern forming and bifurcation theory perspective. Applying advanced analytical and numerical methods, I will first elucidate the origin of light bullets,  characterizing  their  dynamics and bifurcation structure. In a second step, I will study the dynamical properties of optical vortices and the potential transition to optical turbulence. In both cases, their interaction dynamics, and the influence of high-order effects and losses will be analyzed. The understanding of such complex dynamics is crucial, and it will enable a tremendous breakthrough in many technological areas such as high-power multimode fiber lasers, optical communication systems, and a large variety of other industrial and biomedical applications.