Self-Aligned Hybrid Nanocavities Using Atomically Thin Materials

Two-dimensional (2D) materials are increasingly being adopted in hybrid photonics via integration with photonic structures, including cavities. The utility of 2D materials for dielectric environment engineering in hybrid nanophotonic devices remains largely unexplored. We demonstrate self-aligned hybrid nanocavities in which 2D material flakes are used to form cavities locally wherever they are placed along the PhC waveguide postfabrication. We successfully fabricated such hybrid nanocavities with various 2D materials on silicon PhC waveguides, obtaining Q factors as high as 4.0 × 10⁵. Remarkably, even monolayer flakes can provide sufficient local refractive index modulation to induce high Q nanocavity formation. We have also observed cavity PL enhancement in a self-aligned MoTe₂ cavity device with an enhancement factor of about 15. Our results highlight the prospect of using such 2D material-induced PhC nanocavities to realize a wide range of photonic components for hybrid integrated photonic circuits.