  We demonstrate topological defect lasers in a GaAs membrane with embedded
InAs quantum dots. By introducing a disclination to a square-lattice of
elliptical air holes, we obtain spatially confined optical resonances with high
quality factor. Such resonances support powerflow vortices, and lase upon
optical excitation of quantum dots, embedded in the structure. The spatially
inhomogeneous variation of the unit cell orientation adds another dimension to
the control of a lasing mode, enabling the manipulation of its field pattern
and energy flow landscape.
