Tailorable three-dimensional distribution of laser foci based on customized fractal zone plates

S H Tao, B C Yang, H Xia and W X Yu
There is high demand for a tailorable three-dimensional (3D) distribution of focused laser beams for simultaneous optical manipulation of multiple particles separately distributed in 3D space. In this letter, accurate control of the 3D distribution of laser beam foci is demonstrated with an array of customized fractal zone plates (FZPs). The FZPs are designed with a fractional number of fractal segments, so the focal lengths of the foci can be finely tailored. The unique focusing properties of the customized FZPs are investigated with both simulations and experiments. The FZP beams are also found to possess the self-reconstruction property, which would be useful for constructing 3D optical tweezers.

DOI