Volumetric multiple optical traps produced by Devilís lenses

We propose the use of a new diffractive optical element coined Devilís Vortex-Lens (DVL) to produce optical tweezers. In its more general form it results as the combination of a Devilís lens and a helical vortex phase mask. It is shown that under monochromatic illumination a DVL generates a focal volume with several concatenated doughnut modes that are axially distributed according to the self-similarity of the lens. The orbital angular momentum associated to each link in the chain is investigated.