Research On Generation And Regulation Of Self-accelerating Beams With Tunable Propagation Trajectory

In recent years,people have studied the beams from the diffracting Gaussian beam to the non-diffracting Bessel beam,from the Bessel beam propagating along straight line to the Airy beam and the generalized self-accelerating beams with self-accelerating characteristics.These beams have not only been realized in experiment,but also been widely used in many fields such as plasma channels,optical micro manipulation and laser medical treatment because of their novel properties.In this paper,we introduce the research background and the research status of self-accelerating Airy beam at home and abroad.As a research foundation of the thesis,the basic theory of self-accelerating Airy beam is introduced,then the properties of Airy beam including self-acceleration,non-diffracting and self-healing are introduced.To realize the regulation of the Airy beam,we introduce a rotation angle factor into the cubic phase of the common Airy beam combined with the coordinate rotation theory to obtain the Quasi-Airy beam.By changing the rotation angle factor,we can flexibly adjust its intensity distribution and propagation direction.In the meantime,we theoretically and experimentally explore the non-diffracting,self-healing and self-accelerating properties of Quasi-Airy beams.Based on the theory of Quasi-Airy beam,by introducing the linear modulation factor into the cubic phase function,then the Twin-Quasi-Airy beam is induced by binarization processing of the phase.Also,we study its propagating characteristics.Through regulating the above two factors,we can obtain Quasi-Airy beams propagating along arbitrary directions.Concurrently we can change the location of the exit point.The experimental results are in complete accord with numerical results.To achieve the Airy beam with tunable propagation trajectory,according to the knowledge of geometric optics,we firstly demonstrate the quantitative relationship between the spatial frequency of the self-accelerating Airy beam and its parabolic trajectory.We find that the self-accelerating Airy beam can be generated using a 3/2 phase-only pattern.Moreover,we present a simple calculation method,then we can get the phase function of the accelerating beam from a given acceleration trajectory.As an example,the phase function of the accelerating beam propagating along circular,quadratic and logarithmic acceleration trajectory is obtained.Meanwhile,we prove the feasibility of the method by numerical simulation and experimental verification.