Translationally deformed topological charge nanolaser with an ultrasmall mode volume

Developing vortex nanolasers is highly desirable for on-chip multidimensional large-capacity information processing. Topological optical modes hold great promise for achieving coherent emission with diverse functionalities. However, the development of robust and ultracompact topological charge lasing operation remains insufficiently explored. Here, we theoretically propose a translationally deformed topological charge vortex nanocavity with a low mode volume of 0.32 $(\lambda/n)^3$, and experimentally demonstrate the corresponding lasing emission with a low lasing threshold of around 0.74 $\mu$W. The designed topological nanocavity, constructed by translationally deformed photonic crystals, supports an ultracompact optical mode carrying a topological charge characterized by polarization winding. The well-defined topological charge characteristics of the fabricated device are revealed in both near- and far-field polarization-resolved optical profiles. Our work opens a promising avenue for versatile topological photonic integration and gives new potential for exploring intriguing structured light-matter interactions under the topological photonics scenario.