Micro-displacement detection of nanofluidic fluorescent particles based on waveguide-concentric ring resonator model

The dynamic tracking and detecting of nanoparticles in micro-nanofluids have always been a challenging and demanding task. In this work, an integrated model of waveguide-concentric ring resonator is proposed based on the waveguide-concentric ring resonator. The change of the fluorescence power intensity outputted by the cavity coupling structure is used to realize the micro-displacement detection of nanoparticles in the micro-nano fluid. Because the ring micro-resonator has the characteristics of high Q and the sensitivity to the surrounding environment, the sensitivity of the device is greatly improved. The finite-difference time domain method is used to study the parameters such as the polarization state of the fluorescence and the distance between the two ring resonators. The double-peak change of the fluorescence output power can be used to detect the displacement of the nanoparticles with high precision. Based on the synchronization of the double-peak changes, the detection can reduce the influence of environmental noise and improve the detection accuracy. The numerical simulation results also confirm that this method can measure the micro-displacement of nanoparticles in nanofluids in a range of 0-1000 nm, providing new directions and ideas.