高功率激光传输过程中散射点对光束质量的影响

为了研究高功率激光传输过程中不透明颗粒引起的光束调制，通过分析这些不透明颗粒的形状和分布特点，建立了位置呈随机分布的高斯状散射点模型，从光束的衍射理论和干涉叠加理论出发，得到该模型下散射点对传输光束质量影响的解析式。数值分析了高斯状散射点的大小、密度、散射面积比及其传输距离对输出光束的近场分布、位相分布和光束透过率的影响，结果显示亚毫米量级散射点的衍射效应引起最大调制可达1．4，光学元件散射面积比小于0．003时才能满足元件透过率大于99．5％的需求。该结果可用于评价高功率激光装置光学元件的加工状况，并对光学元件加工要求和激光装置的洁净度要求有指导意义。

Effects of Scattering Particles on Beam Quality in High Power Laser Transmission

In order to research the opaque particle which can cause light intensity modulation and induce optics damage in high power lasers,by analyzing its characteristics,the scattering particles model whose shape is Gaussian amplitude with a random distribution is set up.Based on diffraction and interference theory,the effect of scattering particles on beam quality is analyzed.By using the numerical method,near-field distribution,phase distribution and transmittance of the output beam can be acquired.The result suggest that the maximum intensity modulation caused by sub-millimeter scattering particles is 1.4,and the demand that optics transmittance is more than 99.5%,when the scattering area ratio is less than 0.003.The result is beneficial to evaluating optics processing and providing optics cleanliness specifications on high power laser facility.