Analysis And Application Of The Spatio-temporal Coherence Of Polarized Speckle

The study of laser speckle and its statistical properties has long been an important topic in the field of physical optics and has received attention because of its wide application in biomedicine,national defense and spaceflight,remote sensing detection,and optical measurement,etc.However,in the past studies of laser speckle phenomena,these random optical fields were mostly treated as scalar optical fields without polarization information and were mainly concerned with statistical properties and the application of intensity distribution of speckle patterns.The study of random polarization speckle generated by the scattering of the vector light field in a random medium has opened up a field for the study of the statistical properties of the optical field as the main direction,but in the related research,it is not clear how the coherence and polarization properties of the polarization speckle field change in the transmission process.In this paper,we study the surface polarization scattering of anisotropic media based on the coherence matrix,explore the relationship between the statistical properties of the polarization speckle field and the microscopic morphology of the anisotropic media,and investigate the influence of the microscopic morphology of the scattering surface on the coherence and polarization properties of the polarization speckle field.In this paper,the statistical properties of the scattered optical field of the polarized speckle spot are analyzed mainly from the following aspects.(1)Based on the coherence and polarization unification theory of the optical field,the traditional concept of laser speckle and its statistical properties is extended to polarization speckle,and the causes of polarization speckle are explained intuitively by the random wandering of two polarization components of the vectorial optical field in the complex plane.In the framework of considering the light field vector theory,the coherence of the polarization speckle field is described by the spatio-temporal correlation function of the random light field,and the variation law of the polarization state when the light field propagates in anisotropic materials is analyzed.(2)Based on the theoretical analysis,the static polarization speckle generated by the birefringent scattering plate is analyzed,and the phase delay introduced by the random rough surface of the birefringent scattering plate is obtained by assuming that the random rough surface of the birefringent scattering plate conforms to Gaussian distribution,and the phase delay introduced by the random rough surface to the optical field conforms to Gaussian correlation,and the coherence matrix of the polarization speckle field is derived based on the principle of the transmission matrix of the optical field,and the correlation function in the coherence matrix is used to study the spatial coherence and polarization properties of the polarized speckle field are studied according to the correlation function in the coherence matrix.(3)The spatio-temporal coherence of the optical field is considered by the transverse motion of the birefringent scattering plate in the plane of the temporal coherence of the dynamically polarized speckle spot is investigated.Based on the static polarization speckle,the relationship between the coherence and polarization characteristics of the dynamic speckle field and the microstructure of the rough surface of the birefringent material is derived,and the effects of the surface microstructure on the coherence time,coherent area,coherence and polarization of the dynamic polarization speckle field at the incidence of differently polarized light are analyzed by simulation.In this paper,through the theoretical and simulation analysis of polarization speckle,the variation laws of coherence and polarization characteristics of static and dynamic polarization speckle are obtained,and the simultaneous reduction of coherence and polarization of polarization speckle field is investigated.These results will help to understand the generation and spatio-temporal evolution of polarization speckle,and thus promote the related theoretical and industrial applications.