针对惯性约束聚变(ICF)等离子体诊断系统中对长焦深光学元件的要求,采用非线性相位拟合法设计了一块孔径150 mm,焦距450 mm,焦深5 mm的长焦深球面透镜。为了验证该方法的可行性和正确性,制作了一块与设计等F数(通光孔径为80 mm,焦距为240 mm)的长焦深透镜,并且测量了平行光经过该透镜后的轴上和横向光强分布。理论和实验结果都表明,采用非线性相位拟合法设计的长焦深透镜可以获得长焦深、小焦斑、小旁瓣的聚焦光束,可以满足诊断系统对长焦深元件的要求。

Aiming at the requirement of long-focal-depth elements used for the plasma diagnosis in inertial confinement fusion (ICF), a spheric lens with 150 mm aperture, 450 mm focus length, and 5 mm depth of focus is designed by nonlinear phase fitting method. In order to verify the correctness and feasibility of this method, a lens with a long-focal-length and the same F numbers (calibre 80 mm, focal length 240 mm) is fabricated. Moreover, the on-axis and transverse intensity distributions of parallel light after passing the lens are measured. The theoretical and experimental result indicates that the beam from the long-focal-depth lens has long focal depth, small focal spot and side lobe and it can meet the requirements of inertial confinement fusion.