Study On The Purity Structure Of Polarized Light And Its Interaction With Material Media

In this thesis,geometrical interpretations of the structure of polarimetric purity of polarized light and its interaction with material media have been theoretically studied.Firstly,a physically realizable diagram for the polarized light scattering measurement using polarimetric purity index-depolarization index(PI4D-P?)plane is proposed.Subsequently,the concept is extended to understand the structure of polarimetric purity of the plane wave and arbitrary wave polarization states using the N-dimensional polarization algebra.Secondly,the geometrical representation of the purity-depolarization relations with the information on the sources of depolarization has been given in a three-dimensional purity index-components of purity(PI4D-CP)space.Thirdly,these graphical representations are used to study the complete depolarization behavior of polarized light scattering from some biological media.A novel parameter,the overall polarimetric purity index is proposed by considering an equal quadratic average of the indices of polarimetric purity associated with the polarization states of light and material media.The overall purity index ranges from 0 to 1.The maximum value of 1 represents a polarization state with the optimum degree of polarization,while a minimum of 0 corresponds to a completely depolarized light.For the case of light transformed from media,the two extreme values of 0 and 1 stand for the depolarizing and pure(non-depolarizing)media,respectively.On the one hand,the overall polarimetric purity index gives an overall estimate of the polarimetric purity of polarization states and material media,on the other hand,due to its simple construction as an equal quadratic average of the indices of polarimetric purity,it renders the structure of polarimetric purity.Moreover,it forms simple physical constraints with the depolarization index associated with the material media.Through the overall purity index,physical bounds to the purity-depolarization relations for polarized light and light-matter interaction have been studied.With this approach,a decade old problem of the unexplained region in the entropy-depolarization(S(M)-P?)diagram is resolved.Furthermore,by defining the overall purity index for an N-dimensional coherency matrix,the geometrical interpretations of the structure of polarimetric purity of the non-paraxial(with N=3)wave have been presented in the present work.Since the PI4D-P? plane is useful in describing the structure of polarimetric purity,it does not give information on the sources of depolarization.Nevertheless,another physically realizable PI4D-CP space to study the structure of polarimetric purity with the information of the sources of depolarization via indices of polarimetric purity and components of purity has been proposed.Analysis and interpretations based on these illustrations have been employed to understand the microscopic characteristic features of some biological tissues.Thus,in this thesis work,elegant geometrical representations of the complete structure of polarimetric purity of the 2D and 3D polarization states of light,and light transformed from material media using the Stokes-Mueller and coherency matrix formalisms are presented,which give a remarkable physical insight of the polarization problem.