Research On Scattering Of Partially Coherent Light By PT-symmetric Medium

All light fields in nature fluctuate randomly,and this light is called partially coherent light.The study of light scattering from media has the widespread application in many areas such as astronomy,biomedicine,polymer chemistry and meteorology.The scattering of partially coherent beams from various media has also been investigated extensively.In this paper,the optical properties of the scattering field are studied under the condition of first-order Bonn approximation,where partially coherent beam was scattered by paritytime(PT)-symmetric scattering medium.First,we introduce the background and current situation of this dissertation.The theory of scalar light and vector light scattering through deterministic medium is given,and we extend this theory to partially coherent beam.Then,the scattering medium is divided into deterministic scattering medium and random scattering medium according to the randomness of the potential function.Then,we study the scattering property of a normally plane wave scattered by random media whose potential correlation function has PT or classical symmetry.Based on the weak potential-scattering theory,we indicate analytically that the distribution of spectral density in far-field is centrosymmetric,when the random media satisfy classical symmetry.However,the distribution of spectral density becomes asymmetric for the PTsymmetric random scatterer.The reason is the odd-symmetric distribution of the phase in the potential correlation function of the PT-symmetric random media.We demonstrate numerically this point though two types of potential correlations,i.e.,Schell-model correlation and nonuniform-correlated correlation.Subsequently,we give the expression for polarization matrix in far-field of a partially coherent radially polarized beam though scattered medium.We demonstrate both analytically and numerically that the scattered far-field becomes non-centrosymmetric and the directionality appears in the scattering pattern when the scattering potential function is switched from classic symmetry to PT symmetry.We show the effect of spatial coherence of the partially coherent vector beam on scattering.We find that the directionality in the far-zone can be suppressed or enhanced by turning the symmetry property of the spatial coherence function of the incident beam.Finally,we summarize the research content,and put forward some prospects for PT symmetric scattering media.