在千焦耳拍瓦高功率放大系统设计中, 激光脉冲的时空和光谱整形技术一直受到人们的广泛关注。利用经光学微纳超精细加工而成的电介质结构反射镜可在高功率条件下实现啁啾脉冲的光谱整形。在光谱整形介质结构反射镜的设计与制造中, 需要根据加工精度来合理设计数控加工的控制结构函数以及加工刻蚀深度结构函数。针对神光Ⅱ千焦耳拍瓦高功率放大系统设计中提出的多层介质光谱调制反射镜, 推导出数控加工的控制结构函数及其刻蚀深度结构函数, 并通过数值模拟计算, 分析了调制结构反射镜逼近调制函数的效果及其光谱调制特性。

In order to compensate the gain-narrowing and gain-saturation effects and improve the signal-to-noise ratio (SNR) of the output high-power laser pulse, attentions have been paid to the spatial distribution, the temporal profile, and the spectral reshaping in the design of kilo-joule peta-watt chirped pulse amplification (CPA) systems. The multilayer dielectric thin film reflector fabricated by top-down nano-fabrication processes can be used to realize spectral reshaping of high-power chirped pulse. In the design and fabrication of the multilayer dielectric thin film reflector, it is necessary to determine the fabrication control functions appropriately. The control construction function of digital-control fabrication and the etching depth construction functions of the multilayer dielectric thin film reflector for spectral reshaping of chirped pulse laser in Shengguang-Ⅱ system are investigated. The spectral modulation properties of the multilayer dielectric thin film reflector have been analyzed, and the effect of the reflectivity distribution of the multilayer dielectric film reflector approaching to the object function has also been observed.