Perfect vortex in three-dimensional multifocal array.

We proposed an approach for creating three-dimensional (3D) multifocal perfect vortices arrays by using a high numerical aperture objective. The position, orbital angular momentum states, number and diameter of the perfect vortices can be freely modulated by a special designed hybrid phase plate (HPP). HPP could be calculated by 3D phase shifting expression which is derived from Fourier transform theory of the Debye diffraction integral. Furthermore, we developed a novel pixel checkerboard method for adding phase information into the HPP. The segmentation of HPP is related to vortex quality and intensity uniformity. This method could fully use each pixel to modulate the light, since the spatial light modulator has to be used. Small size lattices could generate high quality and uniform intensity vortex arrays in tight focusing region, which may have potential applications in coupling, optical coding and decoding.