Topological insulator laser: Theory

TLDR

Topological insulators are phases of matter with unidirectional, disorder‑robust edge states, making them attractive for quantum computation and spintronics. The authors propose the topological insulator laser as a new concept exploiting topological effects. This concept uses topological edge states to achieve lasing without magnetic fields. The topological insulator laser exhibits topologically protected transport, high efficiency, single‑mode lasing even at high gain, robustness to defects and disorder, and enables high‑power single‑mode arrays while revealing new insights into disorder–lasing interplay.

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. We propose a 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 arrays of semiconductor lasers that operate as one single-mode high-power laser coupled efficiently into an output port.