Topological defect lasers
  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. 
Sebastian Knitter, Seng Fatt Liew, Wen Xiong, Mikhael I. Guy, Glenn S.   Solomon, and Hui Cao
physics.optics