# Interlayer Exciton Laser with Extended Spatial Coherence in an Atomically-Thin Heterostructure

## TL;DR

This paper demonstrates lasing using interlayer excitons in atomically thin heterostructures, achieving extended spatial coherence and highlighting their potential for integrated, low-power nanophotonic devices.

## Contribution

It introduces a novel lasing medium based on dipolar interlayer excitons in 2D heterostructures, with experimental evidence of lasing and enhanced spatial coherence.

## Key findings

- Lasing observed from interlayer excitons in heterostructures.
- Sharp increase in spatial coherence across lasing threshold.
- Interlayer excitons serve as a silicon-compatible coherent medium.

## Abstract

Two-dimensional semiconductors have emerged as a new class of materials for nanophotonics for their strong exciton-photon interaction and flexibility for engineering and integration. Taking advantage of these properties, we engineer an efficient lasing medium based on dipolar interlayer excitons, in rotationally aligned atomically thin heterostructures. Lasing is measured from a transition metal dichalcogenide hetero-bilayer integrated in a silicon nitride grating resonator. A sharp increase in the spatial coherence of the emission was observed across the lasing threshold. The work establishes interlayer excitons in two-dimensional heterostructures as a silicon-compatible coherent medium. With electrically tunable light-matter interaction strength and long-range dipolar interactions, these interlayer excitons promise both applications to low-power, ultrafast laser and modulators and rich many-body quantum phenomena.