多光束纳秒紫外激光制作硅表面微结构

使用波长351 nm的半导体泵浦全固态脉冲激光器（DPSSL）作为光源，经过位相光栅分束，形成干涉光场，在硅表面直接刻蚀微结构，制作了周期为0.55 µm，槽深可达55 nm的一维微光栅和周期为1.25 µm，刻蚀深度45nm的正交微光栅结构。给出了微光栅形貌结构的扫描电子显微镜(SEM)和原子力显微镜(AFM)的测量结果。正交微光栅的一级衍射效率在1.8%到6.3%之间。该研究是改变硅表面微结构，优化硅材料特性的一种新方法，并扩展了大功率激光刻蚀在表面微加工领域的应用。

Dynamic Temperature Field in High Power Double-clad Fiber Laser

According to the heat conduction equation,the temperature distribution in high power double-clad fiber laser (DCFL) was analyzed.The dynamic characteristics of the temperature in the core was discussed.For the fiber with core radius of 15 μm,the computation indicates that the temperature reaches the maximum after opening the pump light for about 20 seconds.Shut down the pump light for about 20 seconds,the fiber will be cooled down to the room temperature.If pumping with pulse light,the temperature will fluctuate at the same frequency with the pulse.The higher the frequency is,the smaller the fluctuate is,the more similar with the continuous pump.