Topological bulk laser and method based on band inversion and reflection of optical field

Abstract

A topological bulk laser includes a topological photonic crystal () having an energy band inversion between dipole mode and quadrupole mode near the center of Brillouin zone and a trivial photonic crystal () not having band inversion for splicing to each other. The reflection and confinement of an optical field occurs at the interface; and the interface encloses to form a closed contour, thereby forming a laser cavity with an effective cavity feedback for lasing at the interior of the interface. This band-inversion-induced reflection mechanism induces single-mode lasing with directional vertical emission. At room temperature, the topological bulk laser can achieve low threshold, narrow linewidth, and a high side-mode suppression ratio, reduce the fabrication difficulty and costs, and improve heat dissipation and electrical injection efficiency, hence improving lifetime and stability of devices.