  We experimentally investigate spatio-temporal lasing dynamics in
semiconductor microcavities with various geometries, featuring integrable or
chaotic ray dynamics. The classical ray dynamics directly impacts the lasing
dynamics, which is primarily determined by the local directionality of
long-lived ray trajectories. The directionality of optical propagation dictates
the characteristic length scales of intensity variations, which play a pivotal
role in nonlinear light-matter interactions. While wavelength-scale intensity
variations tend to stabilize lasing dynamics, modulation on much longer scales
causes spatial filamentation and irregular pulsation. Our results will pave the
way to control the lasing dynamics by engineering the cavity geometry and ray
dynamical properties.
