Research On Single Fiber Optical Tweezers Based On Hollow Annular Core Fiber

Optical tweezers are powerful tools for manipulating microscopic objects,including living cells.Compared with traditional lens-based optical tweezers,the fiber-based optical tweezers have the advantages of simple structure,low cost and easy operation.In recent years,fiber-based optical tweezers have realized particles trapping,moving,rotating and transportating.These technologies are widely used in cell analysis,disease diagnosis,drug delivery.The ability to flexibly manipulate cells in a fluid and further transport it to a designated location has proven to be critical.Therefore,a portable method for cell manipulation and aseptic transmission is urgently needed.In this paper,a single fiber optical tweezers based on hollow annular core optical fiber is studied,which can traping and manipulate yeast and polystyrene spheres.The microfluidic channels integrated into the optical fibers are used to achieve the sterile transport of trapped particles,which is suitable for selective manipulation and transport of rare living cells.And it is of great significance for medical testing and cell analysis.The probe of fiber-based optical tweezer can be implanted into the microfluidic platform to provide a solution for the optional optofluidic technology,which is not limited by the transmission path on the substrate,and reduce the manufacturing cost and difficulty.In this paper,the background,significance,development process and research status of optical tweezers technology are briefly reviewed and summarized.We focus on combing the development status of fiber-based optical tweezers,including multi-fiber optical tweezers,single-fiber optical tweezers and new optical tweezers.The mechanism of optical tweezers based on optical radiation pressure is analyzed,and the transmission characteristics of annular core optical fibers are analyzed.According to the structure parameters of hollow annular core optical fiber,the mode analysis of annular waveguide is carried out,the optical tweezers probe based on hollow annular core optical fiber is designed,and the optical field of the optical tweezers probe is simulated and analyzed.Finally,the distribution of the axial and transverse optical trapping forces is obtained by using the finite element method.The influence of the refractive index and diameter of the microspheres on the optical trapping forces is discussed in detail.In this paper,a single fiber optical tweezers based on hollow annular core fiber is designed,and the experimental system of single fiber optical tweezers is fabricated and built.In the experiment,three-dimensional capture and manipulation of yeast and polystyrene spheres with different sizes were completed.After connecting the inner channel of the optical fiber and the syringe,the micro injection pump is used to control the velocity and direction of the fluid,and the liquid viscous force acting on the captured particles is adjusted and controlled.The optical trap force is controlled by adjusting the laser power.The transport of polystyrene microspheres was realized by adjusting the laser power and flow rate.At the same time,polystyrene spheres can be transported aseptically from the original liquid environment to the new liquid environment by using optical fiber microfluidic channels,which can be applied to the classification of rare cells and broaden the application field of optical fiber tweezers.