  Optical knots and links have attracted great attention because of their
exotic topological characteristics. Recent investigations have shown that the
information encoding based on optical knots could possess robust features
against external perturbations. However, as a superior coding scheme, it is
also necessary to achieve a high capacity, which is hard to be fulfilled by
existing knot-carriers owing to the limit number of associated topological
invariants. Thus, how to realize the knot-based information coding with a high
capacity is a key problem to be solved. Here, we create a type of nested vortex
knot, and show that it can be used to fulfill the robust information coding
with a high capacity assisted by a large number of intrinsic topological
invariants. In experiments, we design and fabricate metasurface holograms to
generate light fields sustaining different kinds of nested vortex links.
Furthermore, we verify the feasibility of the high-capacity coding scheme based
on those topological optical knots. Our work opens another way to realize the
robust and high capacity optical coding, which may have useful impacts on the
field of information transfer and storage.
