Study On Optical Tweezers With Annular Beam

Optical tweezers is a device which uses highly focused laser beam to move the small transparent particles. Optical tweezers since birth, with its advantages indirect contact and no damage to particles, living cells and organelles, etc, is widely used in various fields, especially in the field of life science. Compared to the traditional single Gaussian beam, annular beam has many advantages in the application of optical tweezers, such as the capacity to capture low refractive index particles, the low thermal damage, the capacity to control multiple particles and to increase axial capture range, etc. This paper systematically introduces the basic problems of optical tweezers such as the generation, development, principle and constitution of the system. On this basis, this paper emphasizes the related questions of annular optical tweezers, and the main work is completed as following:1. The types, the methods for generating and the main parameters of the annular beam are discussed.2. The principle of producing an annular beam by a single axicon is introduced in detail, and we use the geometrical optics and MATLAB to describe the propagation of annular beam produced by a single axicon in the system consisting of a pair of lens.3. The theory analysis to describe the propagation of annular beam in the system consisting of a pair of lens is verified by the experiments.4. Suppose we introduce the annular beam into optical tweezers. Numerical simulation of capture efficiency of annular beams with different duty cycle illustrates the annular beams can improve the efficiency of axial capture, and the best duty cycle to improve the efficiency of axial capture is obtained. 5. The annular beam optical tweezers capture multiple yeast cells is carried out.