High-Q Emission from Colloidal Quantum Dots Embedded in Polymer Quasi-BIC Metasurfaces.

Metasurfaces supporting narrowband resonances are of significant interest in photonics for molecular sensing, quantum light source engineering, and nonlinear photonics. However, many device architectures rely on large refractive index dielectric materials and lengthy fabrication processes. In this work, we demonstrate quasi-bound states in the continuum (quasi-BICs) using a polymer metasurface exhibiting experimental quality factors of 305 at visible wavelengths. Our fabrication process only consists of electron-beam lithography and resist development, making it compatible with large-scale fabrication techniques. Additionally, we address the challenges of integrating colloidal quantum dots (CQDs) into the nanopillars, such as depletion-induced aggregation and excess nanoparticle removal, by leveraging our previously reported nanoparticle functionalization method and modified development procedures. We demonstrate both narrowband and polarized emission from our CQD-integrated quasi-BIC metasurfaces. Our proposed metasurface platform is broadly applicable across various quantum emitters and fabrication methods and could enable advancements in scalable manufacturing of resonant optical devices.