title: Generation of second-order vortex arrays with six-pinhole interferometers under plane wave illumination.
abstract: We propose a method based on six-pinhole interferometers to generate vortex arrays with topological charge 2, only with plane wave illumination. The six-pinhole interferometer is composed of two concentric symmetrical three-pinhole interferometers with different radial distances of the pinholes and a relative rotation of 60 deg from each other. In the Fourier domain, the vortices with second-order topological charge are generated when the radial distances of the two three-pinhole interferometers satisfy some certain ratios. Due to the symmetry of the six-pinhole interferometer, such vortices are distributed at the vertices of some symmetrically distributed regular hexagons. The experimental results obtained in a focal-to-focal system show satisfactory coincidence with the calculations.
authors.forename: Zhenhua
authors.initials: Z
authors.lastname: Li
authors.forename: Chuanfu
authors.initials: C
authors.lastname: Cheng