Recent research in topological photonics has not only proposed and realized novel
topological phenomena such as one‐way broadband propagation and robust transport of …

The topological properties of an object, associated with an integer called the topological
invariant, are global features that cannot change continuously but only through abrupt …

Originating from the studies of two-dimensional condensed-matter states, the concept of
topological order has recently been expanded to other fields of physics and engineering …

Topological insulators—materials that are insulating in the bulk but allow electrons to flow
on their surface—are striking examples of materials in which topological invariants are …

Topology describes properties that remain unaffected by smooth distortions. Its main
hallmark is the emergence of edge states localized at the boundary between regions …

We find topological band structures in photonic time crystals—materials in which the
refractive index varies periodically and abruptly in time. When the refractive index changes …

Topological photonics is a rapidly emerging field of research in which geometrical and
topological ideas are exploited to design and control the behavior of light. Drawing …

The orbital degrees of freedom play a pivotal role in understanding fundamental
phenomena in solid-state materials as well as exotic quantum states of matter including …

The discovery of higher‐order topological insulator metamaterials, in analogy with their
condensed‐matter counterparts, has enabled various breakthroughs in photonics …

Topological protection in photonics offers new prospects for guiding and manipulating
classical and quantum information. The mechanism of spin-orbit coupling promises the …