High-Figure-of-Merit Biosensing and Enhanced Excitonic Absorption in an MoS₂-Integrated Dielectric Metasurface

Area of Science:

• Nanophotonics
• Materials Science
• Biosensing

Background:

• Transitional metal dichalcogenides (TMDCs), like molybdenum disulfide (MoS₂), offer high absorptivity for biosensing.
• Dielectric metasurfaces provide a platform for optical biosensing with low losses and enhanced near-fields.
• Functionalizing metasurfaces with TMDCs can lead to strong photon-exciton interactions.

Purpose of the Study:

• To theoretically integrate a single layer of MoS₂ into a CMOS-compatible asymmetric dielectric metasurface.
• To investigate the potential of this integrated system as a high-figure-of-merit (FoM) van der Waals-based biosensor.
• To explore enhanced excitonic absorption and emission applications.

Main Methods:

• Theoretical integration of a single layer of MoS₂ into a TiO₂/SiO₂ asymmetric dielectric metasurface.
• Numerical simulations to analyze the biosensing capabilities and optical properties.
• Investigation of quasi-bound states in the continuum and critical coupling phenomena.

Main Results:

• The designed MoS₂-integrated metasurface functions as a high-FoM (137.5 RIU^-1) van der Waals biosensor.
• Quasi-bound states in the continuum support the high sensitivity of the biosensor.
• A 55% enhancement in excitonic absorption is achieved due to critical coupling between metasurface resonances and MoS₂ A exciton.

Conclusions:

• The proposed MoS₂-integrated dielectric metasurface is a promising platform for effective biosensing.
• The design is practical for applications requiring enhanced excitonic absorption and emission.
• This work highlights the synergistic potential of TMDCs and dielectric metasurfaces in nanophotonics.