Description
Bound states in the continuum (BICs) have drawn extensive attention in optics and photonics due to their ultrahigh quality (Q) factors, which make them ideal for high-sensitivity sensing applications. Existing approaches to realize BIC-supporting nanostructures in the optical regime often rely on expensive and complex fabrication methods such as electron beam lithography. Here, we propose a self-assembly-based method to fabricate photonic crystal (PhC) slabs working in the optical regime. In the fabricated PhC slab, the symmetry-protected BIC was directly observed. By integrating the PhC slab into a microfluidic chip, we characterized the related quasi-BIC mode and demonstrated its sensing performance in various concentrations of NaCl solutions, achieving a sensitivity of 110 nm/RIU.
