为了提高飞秒激光加工的效率和灵活性, 设计了一套飞秒激光全息并行加工系统, 并对该系统中加载计算全息图(CGH)生成的多焦点均一性和空间位置分布的关系进行了研究。首先, 将空间光调制器(SLM)引入飞秒激光加工光路; 然后, 采用GS(Gerchberg-Saxton)算法设计了直线型和三角型分布的三焦点阵列。最后, 通过数值仿真和实验研究比较了用两种不同空间分布的焦点列阵设计的全息图对均一性的影响。 结果表明, 在焦点阵列间距较小的情况下, 直线型分布设计的焦点阵列不易获得好的均一性, 三焦点U仅有79%; 而用三角型分布焦点阵列设计时, 可以获得很好的均一性, 三焦点U约等于100%。实验数据表明, 三角形分布的三焦点可以实现高质量的并行加工, 加工的半球状微结构阵列具有微透镜阵列的功能。

To improve the efficiency and flexibility of femtosecond laser fabrication, a holographic femtosecond laser parallel fabrication system was built. The relationship between the uniformity and the spatial distribution of multi-foci generated by Computer-generated Hologram (CGH) was studied. Firstly, a Spatial Light Modulator (SLM) was introduced into the femtosecond laser fabrication system. Then, Gerchberg-Saxton(GS) algorithm was used to design three foci arrays of straight-line distribution and triangular distribution. Finally, the effects of holograms designed by foci arrays of straight-line distribution and triangular distribution on the uniformity were compared by numerical simulation and experiments. The results show that the foci array of straight-line distribution is not easy to obtain higher uniformity, and its three-foci U is only by 79%; however, that of the triangular distribution tends to achieve higher uniformity and its three-foci U is about 100%. The experiment shows that the three foci of triangular distribution can implement a high quality parallel processing and obtained hemispheric microstructures have microlens array functions .