On The Propagation Variations And Revivals Of The Vectorially Transverse Structure Of Paraxial Light Fields

The transverse structure of paraxial light field and its evolution during propagation can be described by the paraxial wave equation,and its vector characteristics can be represented by the polarization state.The vector structure light field has a spatially heterogeneous polarization state,which is derived from the inherent spin-orbit coupling(Spin-Orbit Coupling.SOC)effect of the light field,and is an optical SOC state.In recent years,the exploration of the physical nature and potential applications of vector structured light with propagation-invariant transverse structures has led to the development of many fields of modern optics and photonics.At present,the research on the vector structure light field is only confined to the vortex beam with simple transverse distribution and radial symmetry.On the one hand,the study of the imaging law of the complex mode vector structure light field will provide a theoretical basis for the propagation and regulation of the spatial structure light field,and on the other hand,it can expand the application space of the vector structure light field in the regulation of the interaction between light and matter.Based on the influence of intramodal phase on transverse structure of paraxial light field,topological origin of Gouy phase,visual description of vector structured light and experimental preparation techniques.Starting from the eigenmodes of paraxial wave equation,the non-eigen vector mode of paraxial field is constructed by superposition of different eigenmodes.This paper focuses on the propagation characteristics of vector structured light based on the Laguerre-Gaussian LGpl(p is radial index,l is angular index)model,as well as its preparation and characterization methods.On this basis,the influence of Gouy phase on the light field of the vector structure is analyzed for the eigen and non-eigen vector modes of different modes order(LGpl mode superposition),and the propagation evolution law of the transverse structure in free space is explored.Finally,based on the complex amplitude modulation of spatial light modulator,different types of vector structured light fields were prepared experimentally,and the propagation law of vector structured light fields was studied according to the fractional order Gouy phase,which verified the accuracy of the theoretical prediction.In this paper,we study the fractional Gouy phase accumulated by the non-eigen vector modes with different order of eigenmodes,which leads to the change of the polarization profile and intensity profile of the vector structural light with the change of propagation distance.On the physical level,it is revealed that the propagation evolution and repetition of the non-eigen vector Gaussian model are caused by the modal Gouy phase difference between the modes in the SOC space and the subspace of the spatial model.This basic principle provides a general guideline for the design of vector structured lights with custom propagation evolution properties.At the technical level,a self-stabilized polarization interferometer is proposed and demonstrated,which can produce arbitrary vector structure light field with high precision and is compatible with digital propagation technology.This technology is of great significance to the generation,regulation and characterization of high-dimensional photon states.