Bound-States-in-the-Continuum-Induced Directional Photoluminescence with Polarization Singularity in WS₂ Monolayers.

Area of Science:

• Materials Science
• Optoelectronics
• Quantum Photonics

Background:

• Monolayer transition metal dichalcogenides (TMDs) are atomically thin materials with direct bandgaps, crucial for optics and optoelectronics.
• However, their room-temperature photoluminescence is randomly polarized, omnidirectional, and weak, hindering practical applications.

Purpose of the Study:

• To achieve spatial control of photoluminescence polarization in monolayer TMDs.
• To enhance the intensity and directionality of photoluminescence for improved device performance.

Main Methods:

• Coupling monolayer tungsten disulfide (WS2) with photonic bands featuring bound states in the continuum (BICs).
• Designing a dielectric photonic crystal slab with BICs that spectrally align with WS2 excitonic resonance.

Main Results:

• Demonstrated spatial control over photoluminescence polarization.
• Modulated emission directionality and enhanced photoluminescence intensity through BIC coupling.
• Achieved improved light extraction and excitation efficiency.

Conclusions:

• Integration of WS2 with BIC-enhanced photonic crystals enables controlled light emission.
• This approach overcomes limitations of random polarization and weak emission in TMDs.
• Facilitates the development of compact, on-chip optoelectronic and quantum photonic devices.