Topological insulator laser: Theory

Abstract

Topological insulators are phases of matter characterized by topological edge states that propagate in a unidirectional manner that is robust to imperfections and disorder. These attributes make topological insulator systems ideal candidates for enabling applications in quantum computation and spintronics. Here, we propose a fundamentally new concept that exploits topological effects in a unique way: the topological insulator laser. These are lasers whose lasing mode exhibits topologically-protected transport without magnetic fields. The underlying topological properties lead to a highly efficient laser, robust to defects and disorder, with single mode lasing even at very high gain values. The topological insulator laser alters current understanding of the interplay between disorder and lasing, and at the same time opens exciting possibilities in topological physics, such as topologically-protected transport in systems with gain. On the technological side, the topological insulator laser provides a route to make many semiconductor lasers to operate as a single-mode high-power laser, while coupled efficiently into an output port.