A single crystal of potassium dihydrogen phosphate (KH₂PO₄, KDP), which possesses unique excellent non-linear electro-optical properties, is currently the only material suitable for electro-optic switches and high power laser-frequency conversion applications in laser-induced inertial confinement fusion. However, KDP crystals are difficult to produce because of their inherent softness, brittleness, and water-solubility, as well as their strong anisotropy and temperature sensitivity. Obtaining high-quality near-lossless KDP elements is an issue that should be solved urgently. In this study, an ultra-precision numerical control polishing method based on the water dissolution principle was introduced to achieve a controllable material removal. A small polishing tool was used to process a large KDP surface, and an accurate tool influence functions is required for deterministic fabrication of KDP surface. In order to quantify the influence of critical parameters (e.g., polishing speed, polishing pressure, water content, and directions of revolution and rotation) on material removal rate distribution, a tool influence function model was established based on the Preston equation. The model was then modified based on experiments, and its accuracy was verified. This modified model lays the foundation for ultra-precision water dissolution polishing of large KDP crystals. A very smoothed surface with high surface accuracy (peak-to-valley value below 0.4 λ) and low surface roughness (Ra 1.598 nm) could indeed be obtained by using the model. This research is also applicable to the polishing of other water-soluble materials.

磷酸二氢钾（KH ₂ PO ₄（KDP）具有独特的优异的非线性电光特性，是目前唯一适用于激光诱导惯性约束聚变中的电光开关和大功率激光频率转换应用的材料。然而，由于KDP晶体固有的柔软性，脆性和水溶性，以及其强的各向异性和温度敏感性，因此难以生产。获得高质量，近乎无损的KDP元素是一个亟待解决的问题。在这项研究中，介绍了一种基于水溶原理的超精密数控抛光方法，以实现可控的材料去除。使用小的抛光工具来处理大的KDP表面，确定性地制造KDP表面需要精确的工具影响功能。。（抛光速度，抛光压力，水含量以及旋转和旋转方向）对材料去除率分布的影响，基于Preston方程建立了刀具影响函数模型。然后根据实验对模型进行修改，并验证其准确性。这种改进的模型为大型KDP晶体的超精密水溶抛光打下了基础。通过使用该模型，可以确实获得非常光滑的表面，具有较高的表面精度（峰谷值低于0.4λ）和较低的表面粗糙度（Ra 1.598 nm）。该研究也适用于其他水溶性材料的抛光。