Interlayer exciton laser of extended spatial coherence in atomically thin heterostructures.

Area of Science:

• Nanophotonics
• 2D Materials Science
• Quantum Optics

Background:

• Two-dimensional (2D) semiconductors offer strong exciton-photon interactions and device integration capabilities.
• Interlayer excitons in 2D heterostructures are promising for novel photonic applications.

Purpose of the Study:

• To engineer an efficient lasing medium using direct-bandgap interlayer excitons in rotationally aligned 2D heterostructures.
• To demonstrate spatially coherent lasing emission from these engineered 2D materials.

Main Methods:

• Fabrication of a transition-metal dichalcogenide heterobilayer (WSe2-MoSe2).
• Integration of the heterobilayer into a silicon nitride grating resonator.
• Measurement of lasing and spatial coherence of the emission.

Main Results:

• Efficient lasing was achieved from the interlayer excitons in the 2D heterostructure.
• An abrupt increase in spatial coherence was observed at the lasing threshold.
• The study establishes interlayer excitons as a viable gain medium for coherent emission.

Conclusions:

• Interlayer excitons in 2D heterostructures can function as a gain medium for coherent lasing.
• These materials hold potential for heterogeneous integration in photonic devices.
• The tunable properties of interlayer excitons suggest applications in low-power lasers, modulators, and quantum phenomena studies.