Control of the spatial characteristics of femtosecond laser filamentation in glass via feedback-based wavefront shaping with an annular phase mask

We propose a feedback-based wavefront shaping with an annular phase mask to control the spatial characteristics of femtosecond laser filamentation in K9 glass. A closed-loop feedback driven by a genetic algorithm was used to search for the optimal phase profile for generating the specified filaments. We demonstrate the flexibility of this method to extend or shorten filaments, improve continuity, and simultaneously control the position of filaments with specified lengths. Our approach offers a flexible regulation of the spatial characteristics of femtosecond laser filamentation for its potential applications.