拼接光栅机械形变对远场光强的影响

分析了将多块较小的光栅使用机械拼接的方式制成超大面积光栅,能解决大面积光栅目前无法整块生产的情况,在实际拼接中光栅会出现很微量的应力变形。根据拼接光栅通常的形变特点,采用标量衍射理论建立了光栅形变的理论模型,并就两块光栅拼接的情况进行了计算和分析,发现形变同拼接误差一样,会对光栅的远场光强产生负面影响,微小的变形量都对远场光强造成破坏,因此对衍射光场的影响不可忽略;获得了光栅机械形变的容限;最后给出了预防形变的措施:可着重减小y方向上约束,并使用多层介质膜光栅降低光栅对能量的吸收。

Influence of mechanical deformation of splicing grating on far-field intensity

Currently, it’s difficult to manufacture large area grating and multiple smaller pieces of grating blocks splice large area gratings.The grating blocks will slightly in splicing process. This paper analyzes the splicing grating’s normal deformation characteristics, builds the theoretical model of deformation, and calculates and analyses the case of two grating blocks splicing. It is found the light field diffraction caused by a tiny deformation can not be ignores. The tolerance of grating mechanical measures to prevent deformation are discussed.