Optical Borromean Vortex Rings

Borromean rings are topological objects made of three inseparable rings, where no two rings are linked with one another. Here we report the first creation of Borromean rings using three-dimensional (3D) structured light. The topological light is constructed from the homotopic mapping of complex braids, followed by the implementation of an accurate adjustment of the vortex lines in a 2D complex space. By carefully tailoring the amplitude and phase distribution of the monochromatic light, we generate the optical Borromean vortex rings within the propagation volume. Full topological reconstruction of the Borromean vortex rings is performed by using digital holography. The topological design method enables the generation of the figure-eight vortex knot family and even more complex topological textures. These findings offer insights into the topological evolution of Borromean rings in other physical systems and pave the way for potential applications in emerging technologies involving light-matter interactions, optical encoding, and quantum information.