Flexible focal array engineering with a binary array vector optical field

In recent years, the vector optical field (VOF) with space-variant polarization distribution has attracted great attention due to its unexpected effects and applications in a wide range of areas. The focal engineering plays the most important role, as the focused VOF provides various interesting properties. Here, we propose a kind of binary array VOF (BA-VOF), which can be applied in focal array engineering. The BA-VOF comprises an array of the first base field of radially polarized VOF and an array of the second base field of superposed subfields with phase modulations. We theoretically design and experimentally generate the BA-VOF. Based on the BA-VOF, we present a flexible method to manipulate the amount of the focal spots in the focal array. Moreover, the polarization state and spin angular momentum of each focal spot in the focal spot array can also be flexibly manipulated. The BA-VOF and the flexibly manipulated focal array are inspirable in the area of structured light, which can be applied in regions needing focal engineering, such as optical tweezers, optical fabrication, optical imaging, and so on.