中文摘要：

基于广义惠更斯一菲涅尔原理，以随机电磁高斯一谢尔模型（GSM）光束作为典型的随机电磁光束，推导了随机电磁GSM光束在生物组织中交叉谱密度矩阵元的解析表达式，并用以研究了其在生物组织中传输时轴上偏振度、方位角和椭圆率的变化。结果表明，随机电磁GSM光束在生物组织中轴上偏振度、方位角和椭圆率的变化与折射率结构常数Cn^2、光束参数（λ,σyy，和σxy）及传输距离z有关；Cn^2越大，轴上偏振度P极值越小，轴上方位角口和轴上椭圆率ε极值越大，且极值对应的传输距离越小；当σyy固定，σxx与yy差值的绝对值越大，P、θ和ε随传输距离的变化率越大；σxy越大，P、θ和ε极值越大；光束在生物组织中传输时，光的偏振态随传输距离的变化范围是很浅的。

英文摘要：

Based on the extended Huygens-Fresnel principle, taking the random electromagnetic Gaussian Schell-model （GSM） beam as a typical example ,the analytical expressions of the cross-spectral density matrix elements for random electromagnetic GSM beam propagating in biological tissues are derived,and used to study the changes above depend on the refractive index of biological tisses Cn^2, beam parameters （λ,σyy and σxy） and propagation distance z. With increasing the Cn^2,the extreme value of P will decrease, θ and ε will increase,and the corresponding propagation distances of the extreme values will decrease. When the σyy is fixed,the bigger absolute value of the difference between σxx and σyy will result in the quicker fluctuation of P,θand ε along the propagation distance. Additionally, the bigger the σxy is, the bigger the extreme values of P,θ and ε are. Finally,the change range in the polarization states of the ran-dom electromagnetic GSM beam with the propagation distance is superficial when propagating in biologi- cal tissues.