Ultra-high sensitivity Bloch surface wave biosensor design and optimization

In this paper, lithium niobate is used as a grating-coupling layer and Bragg reflector defect layer to couple the incident light and break the periodicity of the photonic crystal, which results in localized electric field enhancement and the excitation of Bloch surface waves. By adjusting the incident angle of the light, the structure can achieve two detection modes: surface diffraction detection and guided mode Bloch detection. The average detection sensitivities for the two modes are 452 degrees/RIU and 3170 degrees/RIU, respectively, with maximum detection sensitivities of 480 degrees/RIU and 4380 degrees/RIU. The designed guided mode Bloch detection has the highest sensitivity currently known. (c) 2023 Optica Publishing Group