Annular-focus zone lens and its application

A new method generating diffraction-free beams is proposed. Design scheme is based on Fresnel-Krichhoff diffraction principle. An investigation of the diffraction efficiencies and the transverse intensity distribution on the focal plane of the designed annular focus zone lenses is presented. Computer based simulation results are presented. Its transverse intensity distribution is of stability and of property of the zeroth order Bessel beam. These properties are with no relation over an appreciable propagation distance. The zeroth order Bessel beam have with narrow beam radii, larger intensity. The design device can also produce ring light source. It translates the light of a laser diode into a high intensity narrow width zeroth order Bessel beam. Diffraction-free beams can be used in making VLSI, medical knives, laser prints, memory read write head, high precision collimation,high precision measure. It can be widely used in industrial field and military fields.