The advance of topological photonics has heralded a revolution for
manipulating light as well as for the development of novel photonic devices
such as topological insulator lasers. Here, we demonstrate topological lasing
of circular polarization in a polymer-cholesteric liquid crystal (P-CLC)
superlattice, tunable in the visible wavelength regime. By use of the
femtosecond-laser direct-writing and self-assembling techniques, we establish
the P-CLC superlattice with a controlled mini-band structure and a topological
interface defect, thereby achieving a low threshold for robust topological
lasing at about 0.4 uJ. Thanks to the chiral liquid crystal, not only the
emission wavelength is thermally tuned, but the circularly polarized lasing is
readily achieved. Our results bring about the possibility to realize compact
and integrated topological photonic devices at low cost, as well as to engineer
an ideal platform for exploring topological physics that involves light-matter
interaction in soft-matter environments.Comment: 14 pages, 4 figure