Generalized modified hollow vortex Gaussian beam.

Abstract

Vortex beams have attracted growing interest owing to their unique propagation properties and wide range of applications. This study introduces, to our knowledge, a new model of a vortex beam called a modified hollow vortex Gaussian beam (MHVGB). Based on the Collins integral formula, within the framework of the paraxial approximation, an analytical expression of the propagation of MHVGBs through an ABCD optical system was derived and applied for propagation in free space and through a spherical lens. We compared its propagation properties with those of a hollow Gaussian beam, modified hollow Gaussian beam, and hollow vortex Gaussian beam, which are special cases of the MHVGB, indicating that the modification parameter adds a new dimension of controlling hollow beam properties. Experimental validation of the MHVGB model confirmed its consistency with theoretical predictions. Tight focusing of a radially polarized MHVGB was investigated. The formation of flat-topped beams was observed when specific parameter values were chosen. This vortex beam model may find applications in optical manipulation and particle trapping.