Nondiffracting and self-healing properties of a multi-periodic full Poincaré beam.

In recent years, structured beams have emerged as an attractive and promising area of research, and nondiffracting beams and vector beams stand out as two particularly important categories of structured beams. Recognizing the significance of both beams, it is valuable to build a connection between these two kinds of structured beams. Here, we propose a kind of multi-periodic full Poincaré beam (MP-FPB), whose polarization states can cover the Poincaré sphere (PS) surface multiple times. A nondiffracting ring is generated by the MP-FPB in propagation, which can propagate without diffraction in a certain distance. The polarization of the nondiffracting ring is variant along the azimuthal direction, and the polarization is also stable in propagation. Additionally, the MP-FPB exhibits self-healing characteristics, with its nondiffracting ring demonstrating good self-reconstruction capability. The MP-FPB can enrich the family of the structured light, and the nondiffracting ring with self-healing ability makes the beam resist distortion and preserves the beam's shape. These features not only endow optical beams with exceptional robustness but also facilitate various applications such as optical communication, encryption, optical tweezing, high-resolution microscopy, and quantum informatics.