Utilizing ellipticity to control the focus and propagation of an AGSM beam

At present, the self-focusing focus can be controlled by amplitude, polarization distribution, and coherence, but its application in related fields such as optical field manipulation and laser processing is limited due to the inverse proportionality between laser power and self-focusing length, the discontinuity of topological charge, as well as the invisibility of spatial coherence. In this work, with the spatial light modulator to generate an anisotropic Gaussian Schell-model (AGSM) beam, ellipticity is regarded as a new manipulated degree of freedom, and the continuous and visible tunability of self-focusing focus has been realized for the first time, to the best of our knowledge. Furthermore, an equivalent positive (self-focusing) and negative (thermal-defocusing) lenses competition propagation model is proposed, achieving the precise control of single or multiple foci in the propagation medium. These results provide an approach to flexibly manipulate the self-focusing focus by adjusting the ellipticity, and this competitive propagation model may have potential applications in microfabrication, laser manufacturing, high-power laser propagation and related fields.