Manipulation of the energy flow field in Bessel–Gaussian beams by polarization

Based on vector diffraction theory, this paper investigates the energy flow distribution and its variation characteristics of Bessel-Gaussian beams under polarization modulation. The results demonstrate that on the focal plane, the transverse energy flow with nearly zero intensity and the longitudinal energy flow with very high intensity are obtained, with the longitudinal energy flow dominating the total energy flow field. Furthermore, by adjusting the values of the azimuthal index <i>m</i> and the radial index <i>n</i>, vortex-shaped energy flow distributions can be achieved. The degree of vorticity and the number of energy flow spots can be controlled by adjusting the magnitude of the azimuthal index <i>m</i>, while the direction of the vortex is manipulated by altering the signs of the azimuthal index <i>m</i> and the radial index <i>n</i>. By adjusting the magnitude of the radial index <i>n</i>, size-tunable energy flow rings can be obtained. This polarization modulation strategy offers a novel approach for the flexible manipulation of focused optical fields. Furthermore, the characteristics of energy flow distributions and their dynamic variations will pave the way for new approaches in optical particle manipulation and trapping.