Generation And Control Of Ring Lattice Via Superimposing Ring Airy Beams

Optical lattices are periodic arrays of potential wells generated by laser beam interference and have important applications in atom trap,photonic crystal lithography,microfluidic sorting,super-resolution microscopy,and optical communications.Among them,ring lattices can be generated by superimposing a circularly symmetric structured light field carrying orbital angular momentum(OAM),such as Laguerre-Gaussian(LG),Bessel,and perfect vortex beams,all of which can produce ring lattices of different shapes.The ring Airy vortex beam(RAVB)is also a circularly symmetric structured light field carrying OAM.In recent years,a RAVB superposition carrying opposite chirality and with slightly different radius or width of the main ring has emerged,which propagates in a rotational autofocusing manner and has a higher angular velocity compared with LG and Bessel superposition beams.However,the generation,control and propagation characteristics of the superposition of abrupt auto-focusing waves carrying OAM with the same handedness and associated ring lattices are yet to be investigated in depth.Therefore,this thesis proposes a scheme to generate switchable ring lattices with radial structure based on RAVB superposition,which has potential applications in optical trapping,laser processing,and optical communication.First,a theoretical model of RAVB superposition and propagation evolution is constructed,and the generation conditions and propagation characteristics of bright ring lattice and dark ring lattice are investigated.By studying the propagation of RAVB superimposed beams with the same main ring parameters and different topological charges,it is found that as the propagation distance increases,the bright ring lattice rotates and the radial structure is distorted,forming a chiral lattice,which evolves into a dark ring lattice and a multilayer lattice under certain conditions,and the dark ring lattice also exhibits a similar behavior.By modulating the initial launch angle and propagation direction of the two RAVB,the degree of lattice distortion can be changed and more complex lattice structures can be formed.The physical mechanism of the evolutionary behavior are investigated from the perspective of the RAVB mode decomposition and topological energy flow distribution and it is found that the phase between the RAVB decomposition modes and the change of topological energy flow symmetry with propagation are the underlying reasons of lattice rotation and switching.Second,the theoretical results are experimentally verified using digital propagation techniques.Based on the spatial light modulator complex amplitude modulation,the RAVB spectrum multiplexing hologram was produced,and the coaxial superimposed beams were obtained by Fourier transform,and the bright ring lattice with radial structure and dark ring lattice in the initial plane were generated by tailoring the parameters of topological charge,initial launch angle,and radius of the main ring of the two RAVBs,which confirmed the lattice generation conditions predicted by theory;using the digital propagation technique,the evolutionary behavior of two RAVBs propagating in the same direction and opposite direction is investigated by using digital propagation technique,which confirms the interconversion of bright ring and dark ring lattices and the formation of multilayer complex lattices;the vortex distribution of the main ring of the dark ring lattice and the center of the beam is investigated by using the lattice and plane wave interference method,and it is confirmed that the generated lattice has self-healing property during the propagation.The experimentally obtained lattice spots are in good agreement with the theoretical simulations with an average correlation of 92.7%,and the results can be applied to dynamic microstructure processing on fixed target planes,particle manipulation and optical communication.