Non-iterative dartboard phase filter for achieving multifocal arrays by cylindrical vector beams

We proposed an analytically designed non-iterative dartboard phase filter (DPF) to achieve multifocal arrays by cylindrical vector beams. The DPF is composed of sectors, which is two-dimensionally divided in polar coordinates, along the radial and azimuthal directions. Meanwhile, a modulation factor was first proposed and introduced into the DPF to improve the intensity uniformity of the generated multifocal array. By the proposed DPF, the one-dimensional, two-dimensional and three-dimensional multifocal arrays are generated, which have intensity uniformities larger than 92.5%. The focal position and polarization of these generated multifocal arrays can be controlled, while the transverse sizes of each focal spot are subwavelength. The proposed DPF and the generated multifocal arrays have potential applications in the fields of polarization-multiplexed data storage, polarization-sensitive nanophotonic devices and parallel direct laser writing.