Optimization of laser-induced fluorescence detection system for microfluidic chip

Laser-induced fluorescence (LIF) detection is widely utilized in microfluidic chip due to its high sensitivity and selectivity. In this paper, a LIF detection system for the microscope chip based on a 473 nm laser diode is described. To improve the performance of the detection system, the confocal configuration is adopted in our experiment. Some factors that are important to the signal-to-noise ratio (SNR) of the confocal system, such as the choice of microscope objective, effect of excitation source, the size of pinhole and the performance of the PMT detection units are presented and explained in this paper.