A kind of fiber optical tweezers based on graded index multimode fiber taper and its application method

Abstract

The invention provides a fiber optic tweezers based on a graded-index multimode fiber taper and a method for using the same, belonging to the technical field of fiber optics. The fiber optic tweezers include a graded-index multimode fiber, a single-mode fiber, a capillary glass tube, and a translation stage for fixing the single-mode fiber. There is an air cavity between the single-mode optical fibers. Adjusting the displacement stage can realize the axial movement of the single-mode optical fiber, and then adjust the length of the air cavity, thereby adjusting the capture distance of the optical fiber optical tweezers; one end of the graded-index multimode optical fiber is cut flat end face, the other end is a cone, one end of the single-mode optical fiber is a cut flat end face, the end face of the graded index multimode optical fiber penetrates and is fixed on one end of the capillary glass tube, the single-mode optical fiber The end face of the optical fiber penetrates into the other end of the capillary glass tube. The optical fiber optical tweezers provided by the invention are easy to operate, low in cost, and can realize adjustable capture distance.

Description

technical field [0001] The invention belongs to the field of optical fiber technology, and in particular relates to an optical fiber tweezers based on a graded-index multimode optical fiber taper and a method for using the same. Background technique [0002] Optical tweezers were proposed by Askin in 1986 (Optics Letters, 11(5), 288-290, 1986). The principle is to form a beam of highly converging light based on a converging lens with a large numerical aperture. The particles near the converging point are due to Subject to a large gradient force, it can be captured against its own gravity and scattering force, and can move in three dimensions after capture. Since the use of non-mechanical contact to capture tiny particles will not cause mechanical damage to the particles, and light has strong penetrability to biological particles, optical tweezers are especially suitable for the study of biologically active particles, and are easy to manufacture. It has attracted a lot of at...

AI Technical Summary

Problems solved by technology

[0003] Fiber optic tweezers are made by melting, stretching or chemical etching, usually based on single-mode fiber. However, the core diameter of single-mode fiber is less than 10 microns, which makes these fiber optic tweezers have the following disadvantages: First, the smaller fiber core diameter will limit the radius of the microprism at the fiber tip, making the focusing distance shorter and limiting the capture distance; second, the microprism needs to be made into a special shape at the tip to increase the focusing ability and thus capture The gradient force will make the production process of the cone tip very complicated

Third, if the tapered tip of the single-mode fiber has some defects or the surface is rough, it is easy to cause the light trapped in the core to diverge

However, this method of making fiber optic tweezers has strict requirements on the length of the graded-index multimode fiber taper, and for the same graded-index multimode fiber taper, there is only one capture distance, which does not have the function of adjusting the capture distance. , Poor in operability and applicability

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