Dual-band spectral filter array integrated with a telecentric lens for real-time surface plasmon resonance sensing and imaging

Multispectral and hyperspectral imaging have been extensively applied in various imaging domains, where spectral channels with narrow bandwidths provide detailed information for optical signal analysis. The integration of multi-channel filter arrays with image sensors is essential for multispectral detection. To extend this capability to cameras without integrated filters, a dual-band spectral filter array (DSFA) combined with a telecentric lens was employed with a monochrome camera for real-time surface plasmon resonance imaging (SPRi). Placement of the DSFA in front of a broadband light source generated spatially modulated excitation signals incident on a gold-coated periodic silicon nanostructure serving as a surface plasmon resonance (SPR) chip. A pixel-shift-based demosaicing method enabled the separation of checkerboard-like images into two spectral bands corresponding to the filters of the DSFA, facilitating γ-based spectral contrast response analysis. This optical configuration successfully demonstrated dynamic monitoring of the interaction between anti-BSA and immobilized BSA on the chip. Compared with wavelength-shift analysis, γ-based analysis improved the refractive index detection limit by nearly two orders of magnitude, enabling highly sensitive monitoring of biomolecular interactions. The DSFA-based SPRi platform provides a flexible, highly integrable, and label-free solution for quantitative analysis of biomolecular interactions.