Optically Pumped Monolayer MoSe₂ Excitonic Lasers from Whispering Gallery Mode Microcavities

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Developing integrable, low-energy lasers is essential for optical computing and communications.
• Monolayer transition metal dichalcogenides (TMDs) offer strong exciton-photon interactions for laser engineering.

Purpose of the Study:

• To create and characterize nanoscale excitonic lasers using MoSe2/microsphere cavities.
• To explore tunable lasing properties for on-chip applications.

Main Methods:

• Fabrication of MoSe2/microsphere cavities by placing SiO2 microspheres on monolayer MoSe2.
• Continuous-wave excitation of whispering gallery mode (WGM) cavities.
• Finite Element Method (FEM) simulations using COMSOL for mode analysis.

Main Results:

• Achieved multiple excitonic WGM lasing in the 750-875 nm range at room temperature.
• Demonstrated tunability of free spectral range (FSR) and full width at half-maximum (fwhm) by altering microsphere size.
• Identified lasing modes and electric field distributions through theoretical calculations.

Conclusions:

• The MoSe2/microsphere system provides a promising platform for integrable, scalable, and low-cost laser devices.
• Findings enhance fundamental understanding of excitonic WGM lasing mechanisms.