Designing real-time biosensors and chemical sensors based on symmetrical photonic crystal heterostructures

In this paper, we introduce and analytically demonstrate a novel biosensor based on the light-matter interaction in a classic topological photonic crystal (PC) heterostructure, which consists of two opposite-facing 5-period PCs separated by a microfluidic channel. Because of the excitation of topological edge mode (TEM) at the interface of the two PCs, the strong coupling between incident light and TEM produces a high-quality resonance peak, which can be used to detect very small changes in the refractive index of biomaterials such as Jurkat Cells inside the microfluidic channel. The proposed biosensor has a sensitivity as high as 240 nm/RIU and figure of merit (FOM) higher than 250.