Focusing properties of symmetric broken azimuthally polarized beams modulated by non-uniform spiral phases

The controlling of the distributions of intensity and transversal energy flow in the focal filed of azimuthally polarized beams by multiple parameters was presented. The modulations of non-uniform spiral phase and rotationally symmetric amplitude obstacle on the focusing properties of azimuthally polarized beams were numerically studied, as well as their combined modulation on transversal energy flow and polarization distributions in the focal plane were also analyzed, based on the vectorial diffraction theory. The results demonstrate that the non-uniform spiral phase has significant effects on the focusing properties, and give rise to the shift of gravity of the focused field. With the combined modulation of even-fold rotationally symmetric amplitude obstacle, local elliptical polarization and circular polarization, as well as transversal energy flow appear in the focused field. Additionally, adjusting the phase structure not only can control the gravity of the focused field, but also can further enrich the focal field polarization state and transverse energy flow. This method of controlling the intensity and energy flow of focused field provides a new way to realize the manipulation of particles in special area.