FDTD Simulation And Experimental Study Of Special Single-fiber Optical Tweezers

It is possible to manipulate many different samples with the light of the laser beam alone,opening the way for all kinds of experiments.The technology is called optical tweezers.Using this contactless optical capture technology,single and multiple moving microscopic objects,such as cells and bacteria,can be captured and manipulated.The miniaturization and integration of optical tweezers is a hot research area at present.Unlike traditional lenticular-type optical tweezers,fiber optic tweezers provide a convenient,miniaturized tool for capturing cells,and single fiber optical tweezers are easy to operate and easy to use in practice.In addition to trapping,manipulating and spinning particles,fiber-optic tweezers can also be used to monitor the backscattered light of the trapped particles.With the continuous development of optical tweezers technology,optical tweezers have been widely used in many other fields such as physics,nanotechnology,chemistry,soft matter and nano thermodynamics.This paper presents two new kinds of special single fiber optical tweezers.The first is a modified multimode fiber optical tweezers based on the UV glue cavity.The cavity between the single-mode fiber and the modified multimode fiber probe is filled with UV glue to realize the non-contact trapping of the particles.This kind of gradual multimode fiber optical tweezers based on UV glue cavity has greater optical trapping power and longer optical focusing range.At the same time,the effect of the cavity length on the capture was calculated,and the three-dimensional stable capture of yeast cells was achieved through experiments.By controlling the power to control the capture position of yeast cells,the research can control the lowest power of yeast cells,so as to reduce the laser damage to cells to a minimum.The results showed that the minimum power of yeast cells was 10.8 m W and the control distance was 37.7?m.And the preparation process of the gradual multimode fiber optical tweezers is simple and easy to repeat,which is conducive to the expansion of fiber optical tweezers to the application level.The second is fiber optic tweezers based on doublecore fiber cone.The cavity structure is prepared at the tip of the double-core fiber cone,and the cavity is filled with water and ultraviolet glue.The distribution of the emitted light field is studied by the finite-difference time-domain method,and the axial optical force of the captured particle is calculated.Through a lot of simulation analysis,it is shown that when the cavity is fully injected with UV adhesive,the axial optical force of the silica particles with a diameter of 3?m is the largest,which is up to 50 PN,so the silica particles are easier to be captured.These two new types of special single fiber optical tweezers provide new ideas and theoretical basis for the scientific research workers.