Wavefront reconstruction and absorption modulation of structured light in nonlinear optics

Investigating nonlinear interactions between structured light fields and solid-state media is crucial for understanding physical processes such as topological structure evolution, orbital angular momentum transfer, and frequency conversion. This work presents the first observation of spontaneously formed periodic spatial structures—including multi-orientation stripes, honeycomb arrays, and regular vortices—on newly generated frequency components during femtosecond laser-induced supercontinuum generation. These optical field structures are interpreted as arising from the dynamic self-reconstruction of nonlinear wavefronts within the crystal, without external interference devices. Dual-beam interference confirms that this nonlinear wavefront reconstruction produces multiple optical vortices. Furthermore, we demonstrate that the spatial structure of the pump light modulates nonlinear absorption properties, yielding multistage oscillatory absorption behavior. Our results indicate that dynamic wavefront reconstruction during third-order nonlinear processes constitutes the physical essence of periodic structure formation, offering new insights into mode evolution dynamics. All findings establish the pivotal role of optical field structure control in generating nonlinear optical topological states, and suggest novel approaches for developing broadband orbital angular momentum photonic devices and realizing high-speed vortex optical information processing.