Soft-matter-based topological vertical cavity surface emitting lasers.

Polarized topological vertical cavity surface-emitting lasers (VCSELs) are promising candidates for stable and efficient on-chip light sources, with significant potential for advancing optical storage and communication technologies. However, most semiconductor-based topological lasers rely on intricate fabrication techniques and face limitations in providing the flexibility needed for diverse device applications. By drawing an analogy to two-dimensional Semenov insulators and the quantum valley Hall effect in a synthetic parameter space, we design and realize a one-dimensional optical superlattice using stacked polymerized cholesteric liquid crystal films and Mylar films. Such a one-dimensional optical superlattice is achieved by using films spin-coated with a Pyrromethene 597 solution, thus enabling the demonstration of a structure-flexible, low threshold, and circularly-polarized topological VCSEL. We demonstrate that such a topological VCSEL maintains excellent single-mode operation at low pump power, and its spatial profile aligns closely with that of the pump laser. Thanks to the soft-matter-based metastructure, the topological laser can be "attached" to substrates of various shapes, maintaining desired laser properties and beam steering even after undergoing multiple bends. These characteristics make the demonstrated topological laser ideal for applications in consumer electronics, laser scanning, displays, and photonic wearable devices, where both flexibility and performance are crucial.