Optical Funnel Effect of Fiber-End Conical Shell Light Field

The manipulation and analysis of particles in fluid has always been a matter of concern. In the liquid microfluidic system, the quality of single cell flow directly affects the final analysis results. Due to its special structure, optical fiber has the advantages of simple structure and good compatibility and has become a cross-integration link in various research fields. In this letter, an integrated optical fiber structure for particle manipulation in fluid is proposed. The annular-core capillary fiber developed by the laboratory is adopted, which has the structure of cladding - annular core - air hole. The cone angle of 12° is polished at the exit end of the optical fiber. The laser transmitted by the annular core is reflected by the cone and forms a funnel-shaped cone shell light field at the end of the optical fiber, which is called ‘optical funnel’. When the particles are injected from the air hole and pass through the conical shell light field, the continuous directional control is formed due to the action of the light field force. The device has the characteristics of simple structure and high integration, which provides a solution for the miniaturization of instruments and equipment and is of great significance in engineering applications.