Study Of Polarization Singular Properties And Method Of Modulation In Light Fields

The development of laser technology result in extensive research on the frequency,amplitude and phase of light.Recently,the polarization of light is increasingly used to detect the physical world,which means polarization characteristics of light attracts more and more attention.There appear significant progresses in areas of space communications,remote sensing,target identification and classification,detects of the environment,biomedical diagnostics,and engineering materials testing by applying polarization information in conventional optical technology.The extensive research of the connotation of polarized light corresponds to its own rich hierarchy.However,compared with the high degree of freedom of the polarization states of light,only the basic information carried by polarization was exploited in.these engineering applications.This is due to the lack of theoretical study of distribution of polarization states of field and makes studying the polarization of light become an unavoidable problem of developing the polarization optics.This thesis centers on the research of polarization singular characteristic of light,modulation method of polarization singularities and detection method of polarization singularities.For the research of polarization singular characteristic,the distributions of circularly and linearly polarization singularities and polarization ellipses around these singularities were studied.As for the field in paraxial approximation,pq representation was used to describe the electric vector,and the definition of circularly and linearly polarization singularity were given.By regarding the polarization ellipses around a circularly polarized point as a whole,the patterns and characteristic of polarization singularities were studied,and the discriminant functions of different patterns were given in form of Jones matrix.In order to form a unified description of different polarization singular patterns,the light was decomposed to orthogonal circular polarization vector basis.The conditions and probability of each pattern were discussed.Then the light was decomposed to orthogonal linear polarization vector basis.With the help of auxiliary line,the distribution of amplitude and phase around circularly polarized point were obtained.As for the field in non-paraxial approximation,the definition of true-circularly and true-linearly polarization singularities were given,the major axis of ellipses around these true polarization singularities construct Mobius rings.Based on Rayleigh-Sommerfeld vector diffraction theory,the distribution of true-circularly polarized singularities in diffraction field of two holes was researched.The reason result in exceptional behavior of the major axis of polarization ellipses was discussed.In addition,because of using the boundary conditions to obtain Rayleigh-Sommerfeld vector diffraction equations,the validity of using Kirchhoff boundary conditions on the aperture plane was discussed.To examine the polarization states of optical fields,Stokes parameters were introduced and the definition of polarization singularities and the discriminant functions of different singularities with the parameters were induced.Then the methods to examine Stokes parameters were elucidated and the reasons of transverse shifts in light beams resulting from rotating optical elements were analyzed.Based on the analysis,a examine system for measuring polarization states which can calibrate the transverse shifts was designed and conducted experimentally.The modulation of polarization singularities is another important part of this thesis.Three methods used to modulate the polarization singularties were proposed.To generate the optical fields with arrayed polarization singularities,the method of interference of three light beams was introduced and the arrays that could be generated were summarized.Based on the analysis of amplitudes and phases around polarization singularities,an isolated singularity can be generated and the position of straight lines emitting from the singularity can be arbitrarily modulated by constructing the amplitudes and phases.The work of this thesis provides a theoretical basis for fully application of polarization characterizes.