Optical Spiral Predator–Prey Dynamics

Chase-and-escape motion, which is a typical behavior between a predator and prey, is an important dynamics in animate systems. It has been concerned recently in optics aiming for achieving novel light steering and switching functions. However, this optical counterpart can be realized in only one dimension because of the challenges in maintaining the chase-and-escape interaction. Herein, we report, both theoretically and experimentally, the optical predator–prey dynamics in two dimensions for the first time. Upon nonreciprocal interaction, two beams can form a localized or oblique spiral chase-and-escape motion, which persists owing to the mutual light confinement. Unusual optical phenomena are observed in these dynamics: the angular momentum is not conserved and the resulting transverse traveling motion can be opposite to the applied initial momentum and enhanced by increasing the internal light interactions. The results can inspire further fundamental studies by exploring analogous animate phenomena in optics that are potentially useful for developing optical intelligence functions.