Pure optical detection photoacoustic microfluidic chip for studying two-phase flow droplets

A simple, low-cost and new all-optical photoacoustic droplet microfluidic detection system is proposed by combining the pure optical photoacoustic detection technology based on polarized light reflection with droplet microfluidic chip technology. In this work, we first use Matlab and Comsol to carry out theoretical calculation and simulation of polarized light reflection, the theory and simulation results are highly consistent. In the experiment, a simple and practical microfluidic chip was prepared by the molding method, and the application range of the polarization based pure light photoacoustic microfluidic detection technology was expanded. Firstly, the photoacoustic signals of black tape in microfluidic chips with different pipe heights are tested to verify the feasibility of our system. Then the suitable flow rate and the flow rate ratio of the two-phase flow were adjusted, and a large number of homogeneous droplets were generated. Methylene blue as one of the samples, the photoacoustic signal of methylene blue droplets was detected. The results show that the polarized light based total internal reflection optical system combined with microfluidic chips has great application potential in microfluidic detection.