Creation of needle of transversely polarized beam in vacuum by using complex phase plate

The intensity distribution in the focal region for the tight focusing of double-ring-shaped azimuthally polarized beam with complex phase plate is studied on the basis of the vector diffraction theory. Here we report a new method that generates a transversely polarized light beam with sub diffraction beam size (0.488 λ) that propagates without divergence over a long distance (of about 8.6 λ) in free space. This work is important for optical manipulation and may find applications when using optical materials or instruments responsive to the transversal field only.