Rotating light fields of an azimuthally polarized light beam generated by two-belt spiral phase modulation

ABSTRACTThe tightly focused light fields of an azimuthally polarized light beam through a two-belt spiral phase plate were investigated. The focused light fields are presented in accordance with vectorial diffraction theory. The results show that a rotating light field with different intensity patterns can be produced by altering the azimuthal polarization state and modulating the two-belt spiral phase. A concurrent change in spiral handedness in the two-belt phase plate causes the rotation to occur along the direction of propagation, and the relative angular offset in the two-belt spiral phase plate can be exploited to rotate the light fields. The proposed method is useful for engineering the intensity distribution near the focal plane and related applications.