基于计算全息术的大口径长焦透镜波前检测技术研究

The high-power solid-state laser facility used for the inertial confinement fusion research is of great significance for the state-of-the-art technology, is an irreplaceable experimental tool for strategic high-tech innovation, basic scientific research and cross-disciplinary research. As a key element of the terminal optical system, the wave front of the spatial filter lenses (SFL) determines the focusing performance and imaging quality of the laser beam, therefore should be controlled at full frequency band. The common interferomety method is inoperative due to the large-aperture, long focal length characteristics of SFL, a new method of using the computer-generated hologram (CGH) to provide aspheric reflective wavefront is proposed in this research project, and could enable rapid production measurement of the large SFL with benchtop optical structure while meeting the stringent foals for precision and accuracy. The specific research content as follows: (1) The mathematical model of the CGH method and proof test; (2) The effect of aberrations and diffraction, as well as error correction model; (3) Lens mid-frequency characterization method. As the eyes for optical manufacturing of SFL, the wavefront testing technique is the only means to evaluate the lens and guide the machining process, and is the foundation of precision machining and deterministic machining, therefore it is of great importance to make further research on this topic.

用于惯性约束聚变(ICF)研究的高功率固体激光装置对我国开展尖端科研具有重大意义，是战略高技术创新、基础科学、交叉前沿科学创新不可替代的实验研究工具。大口径长焦透镜作为终端光学系统的关键元件，其波前质量直接决定光束的聚焦性能及成像质量，需实现全空间频段误差控制。大口径、超长焦距的特点使得传统干涉检测方法失效，本项目提出使用计算全息图（CGH）提供非球面反射波前的全新方法，可实现高效、高精度、短距离、非接触的大口径长焦透镜波前检测。具体研究内容涵括三方面：(1)CGH法测量透镜波前数学模型与实验验证；(2)像差、衍射效应等对检测的影响及校正方法；(3)透镜中频波前表征方法。精密检测技术作为加工的眼睛，是评价透镜性能和指导加工的唯一手段，是高性能光学系统研制并具备光学加工的超精密和确定性水平的基础，对其进行深入研究具有重要的科学意义与实用价值。

在强激光及高分辨探测等领域，作为终端光学系统的关键元件的大口径长焦距透镜，其波前质量直接决定光束的聚焦性能及成像质量。然而由于长距离、振动、空气扰动等干扰因素，传统的球面元件波前检测方法无法用于大口径长焦距透镜波前检测。大口径长焦透镜波前检测技术的滞后严重影响了整个光学系统的成像特性和聚焦性能，成为元件加工领域发展和应用的技术瓶颈。. 本项目提出使用计算全息图（CGH）提供非球面反射波前的全新方法，实现高效、高精度、短距离、非接触的大口径长焦透镜波前检测。具体研究内容涵括：(1) CGH法测量透镜波前数学模型与实验验证；(2)像差、衍射效应等对检测的影响及校正方法；(3)透镜中频波前表征方法。通过理论分析与实验验证，对于焦距大于30m、通光口径大于Φ410mm的长焦距非球面透镜，CGH法测量低频波前不确定度小于λ/10（λ=632.8nm），中频波前功率谱密度PSD测量不确定度RMS小于1nm。. 精密检测技术作为加工的眼睛，是评价透镜性能和指导加工的唯一手段，是高性能光学系统研制并具备光学加工的超精密和确定性水平的基础，发展高效、高精度、无损伤的大口径长焦距透镜波前检测技术，并具备相应的工程化能力，对其进行深入研究具有重要的科学意义与实用价值。