Research On Tight Focusing Properties And Radiation Force Of Vector Anomalous Vortex Beams

The laser beams have many excellent properties after passing through a high numerical aperture lens,so they have wide range of applications in the fields of optical capture,material processing,high-resolution imaging,particle acceleration and transmission,atomic optics and molecular optics.Many researchers have studied the deep focusing characteristics of all kinds of beams in detail,such as partially coherent linear polarization vortex beams,various ultrashort pulse beams,radial polarization and angular polarization beam,etc.,and the intensity,coherence and polarization characteristics near the focal plane are studied.On the other hand,because of optical tweezers' precise manipulation,non-contact,and no mechanical damage to the captured particles,they have been widely used in biology and medicine,physical chemistry and materials science.Since the anomalous vortex beams(AVBs)was proposed,the deep focusing characteristics of AVBs have not been studied.Based on the vector Debye integral theory and Rayleigh scattering theory,the paper analyzes the characteristics of the deep focusing field of linearly polarized anomalous vortex beam and circularly polarized AVBs,in addition that,the stability of linearly polarized AVBs and circularly polarized AVBs capturing the Rayleigh particle are analyzed in detailed.The main research contents of the paper are as follows:1?The deep focusing properties of linearly polarized anomalous vortex beams are studied.The expressions of linearly polarized AVBs through a high numerical aperture lens are derived.And the influence of the relative parameters on the intensity distribution near the focal point is analyzed numerically.It is found that the effect of topological charge number m on the intensity distribution is higher than that of the order n,except that,the phase of the deep focus field will reverse when passing through the focal plane.2?The deep focusing characteristics of circularly polarized AVBs are studied.The expressions of circular polarized AVBs through a high numerical aperture lens are derived.The effects of the topological charge and the order on the intensity distribution are discussed numerically,the phase characteristics are also studied.By adjusting relevant parameters,it is found that the deep focusing field of the circularly polarized AVBs can produce a flat-top beam at different propagation planes.Therefore,the circularly polarized anomalous vortex beam can be used as the incident light source to produce flat-top beam in combination with a high numerical aperture lens.3?The radiation force of focusing AVBs is investigated.Based on the previous research contents and the Rayleigh scattering theory,and combining the expression of focusing linearly polarized AVBs and focusing circularly polarized AVBs,we calculated the gradient force and scattering force of Rayleigh particles in deep focusing field,and discussed the stability of capture of particles in deep focusing field numerically.By adjusting the relevant parameters,it is found that the deep focusing field of both linearly polarized AVBs and circularly polarized AVBs can capture low refractive particles or high refractive particles stably.