Propagation behavior beyond approximately six nonlinear lengths in GRIN rods

Characterize the propagation dynamics and output beam behavior of spatially complex, phase-modulated beams in graded-index rods at high input power for propagation distances exceeding approximately six nonlinear lengths, including whether self-cleaning persists or new phenomena emerge.

Background

Due to available component limitations, the experiments probe a relatively short propagation distance in GRIN rods. At the highest power, the authors estimate the length is about six nonlinear lengths, and explicitly state the behavior beyond that is unknown.

Understanding longer-distance evolution is essential for clarifying asymptotic dynamics, potential equilibria, and the applicability of thermodynamic or kernel-based frameworks in the many-mode, low-dispersion limit.