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We propose a new formula to describe the dynamics of holographic grating formation under low intensity pulse exposures in cationic photopolymers, in which the dark reaction contributes dominantly to the grating strength. The formula is based on the living polymerization mechanism and the diffusion-free approximation. The analytical solution indicates that the grating formation time depends on the termination rate constant, while the final grating strength depends linearly on the total exposure energy. These theoretical predictions are verified experimentally using the Aprilis HMC-400μm photopolymer. The results can provide guidelines for the control and optimization of the holographic recording conditions in practical applications. 相似文献
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自动确定方位的激光束指示器 总被引:1,自引:0,他引:1
介绍了一个可以自动确定光束方位的激光束指示器。在立轴支承的转盘中央安装一个平面反射镜,在转盘的圆周边缘处安装一个霍尔传感器。调整半导体激光器,使其激光束的初始方向与立轴同轴,并经反射后水平出射来进行方位指示。利用线性霍尔传感器对地球磁场的敏感性,测出激光束方向与地磁方向的夹角。由单片机控制系统发出指令,由步进电机及精密减速箱驱动立轴转动,通过带动反射镜水平转动来改变激光束的出射方向。指示器工作时,首先应使激光束的方向与地磁方向一致,然后再使激光束转过预定的角度,实现绝对方位角的激光束定向。系统方位角的定位精度可达到0 1′,具有较高的实用价值。 相似文献
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