Chip-based 532 nm band fluorescence excitation-detection sensing system

This paper presents a chip-based fluorescence excitation and detection sensing system operating at a 532 nm visible wavelength. The system consists of a fluorescence excitation chip integrating micro-nano optical devices including multimode interferometers, grating arrays, and Bézier curve waveguides, along with an optical filter and an avalanche photodiode array detection chip. Through front-end optical fiber packaging coupled with the 532 nm laser, the sensing system achieves a centimeter level compact structure. Systematic testing and optimization were conducted on two critical parameters affecting fluorescence collection efficiency: the input optical power of the excitation chip and the emission wavelength band filtered by the optical filter. The results demonstrate that the proposed sensing system exhibits a high sensitivity fluorescence detection, with a limit of detection reaching the nmol/L level, thereby providing a novel approach for point-of-care fluorescence excitation and detection. The system shows promising application potential in fluorescence-based detection fields such as quantitative polymerase chain reaction (PCR) for biological analysis.