Research On Self-focusing Properties Of Circular Airy Beam With Hard-edge Aperture

This paper reviews the three major characteristics of Airy beams:self-bending,non-diffraction,and self-healing.The circular Airy Beam(CAB,Circular Airy Beam)with sudden self-focusing characteristics as the special type of Airy beam is introduced.It keeps the beam hollow before forming the focus,and it spreads to the focus to suddenly concentrate the energy of the beam.Applied to optical manipulation aspect,it makes optical tweezers have stronger gradient force and scattering force,CAB greatly improves the performance of conventional optical tweezers.Therefore,further improving and changing the self-focusing characteristics of CAB has become a research trend in recent years.After reviewing the research on the diffraction of the hard-edge aperture in recent years,it is found that the diffraction focusing effect of the light field passing through the hard-edge aperture will also occur,which has many applications in beam focusing.This paper has carried out research on enhancing the self-focusing of CAB.Based on the study of the diffraction characteristics of the one-dimensional Airy beam under the hard-edge aperture,the first application of the diffractive focusing effect of the hard-edge aperture to enhance the self-focusing of the circular Airy beam is studied,and three kinds of hard-edge aperture(circular aperture,blocking aperture,annular aperture)and different decay factors to enhance and adjust the CAB self-focusing properties.The following main conclusions were obtained:1.This paper finds the diffraction oscillation phenomenon of one-dimensional ideal and attenuated Airy beam after passing through the hard-edge aperture.Studies have shown that the maximum value of the diffraction oscillation of the ideal and decayed Airy beam after passing through the aperture coincides with the focal position of the diffraction focus,resulting in a diffraction focusing effect.2.It is found that the diffractive focusing point of the circular diaphragm coincides with the self-focusing point of CAB,which leads to the enhancement of its self-focusing performance.3.It is found that under different attenuation factors,the hard-edged ring aperture can generally enhance the effect of CAB self-focusing.In addition,the ring-shaped aperture realizes a larger range of higher-efficiency control of the CAB self-focusing peak than the power adjustment.