Far-zone Manipulating Characteristics Of Hollow Schell-model Beams

In the past few decades,researchers have proposed various light sources in the field of beam propagation,and Schell model beams are the most widely studied.The optical characteristics of these kinds of light sources in the area of light field are only determined by the difference of between two position vectors.At the same time,researchers obtained different light sources by constructing different structural correlation functions.These sources will produce different kinds of spectral intensity distributions in the beam field,such as,spatial periodic lattice distribution,ring distribution,rhombus distribution,triangle distribution and so on.In addition,the researchers also added a twisted phase on the source to obtain a twisted light source,which can make the beam rotate around the during propagation.Thus,the twisted phase provides a new degree of freedom for beam field manipulation.The research also shows that the beam with twisted phase can improve the propagation quality of the beam,which has important application value for optical communication in free space.In recent years,all kinds of hollow sources and methods for generating hollow spectral intensity distributions have been realized in theoretically and experimentally.Hollow beams have great significance in particle capture,imaging,treatment of optical surface materials and so on.Therefore,the study of hollow beams has attracted the widely attention of researchers.Four new hollow Gaussian Schell model sources are mainly discussed in this thesis,and the different optical properties of these four hollow sources in the beam field are studied.Moreover,the distributions of spectral intensity under different light source parameters are also discussed.The main research contents are as follows:（i）.The propagation characteristics of rectangular hollow multi-Gaussian Schell model source is studied.The related structure function of source is constructed,the cross-spectral density function of the source plane and far-field are derived and the spectral intensity distribution is also obtained.The influence of the source parameters on the spectral intensity distribution is discussed.The results show that the characteristics of far-field spectral intensity,such as the thickness of the hollow edge,the shape of the hollow,the size and contour direction of the hollow can be effectively controlled by adjusting the parameters of light source.（ii）The propagation characteristics of rectangular hollow twisted multi-Gaussian Shell model source is studied.The related structure function of source is constructed,the cross-spectral density function of source plane and beam field is derived,the spectral intensity distribution is also obtained.The influence of the source parameters on the spectral intensity distribution is discussed.The result shows that the thickness of hollow edge,the size of hollow and the rotation direction of spectral intensity can be adjusted by choosing appropriate structural parameters of source.（iii）The propagation characteristics of twisted hollow Gaussian Shell model rectangular array source is studied.The cross spectral density functions of the source and beam filed are reconstructed,the spectral intensity distribution is also obtained.The influence of the source parameters on the spectral intensity distribution is discussed.The rotation direction of each hollow lobe in the rectangular array,the number of rows and columns in the rectangular array and the distance of between each adjacent hollow lobe in the array can be controlled by adjusting the parameters of the source.（iiii）The propagation characteristics of twisted hollow Gaussian Schell model ring-shaped array source is studied.The cross spectral density functions of the source and beam filed are reconstructed,the spectral intensity distribution is also obtained.The influence of the source parameters on the spectral intensity distribution is discussed.The distribution characteristics of spectral intensity are analyzed in detail by numerical simulation,including the degree of rotation of each hollow lobe in the ring-shaped array with the increase of distance,the rotation direction of each hollow lobe,the number of layers of the ring-shaped array,the number of hollow lobes in each layer and the distance of between two adjacent hollow lobes.