The harmonic generation efficiency of a large aperture KDP (KH₂PO₄) crystal that is used in the Final Optics Assembly of high-energy solid-state lasers is one of the key points to achieve inertial confinement fusion. The variations in the detuning angle of a KDP crystal are achieved by interferometer and calculation. The harmonic generation efficiency is calculated using variations in the detuning angle. The theoretical prediction model of harmonic generation efficiency based on small-signal approximation theory was built. In the experiment, Crystal off-line Debugging System was used to measure the actual harmonic generation efficiency of a KDP crystal. The predictive harmonic generation efficiency of a KDP crystal and the actual efficiency was compared, which concluded that the theoretical prediction model of harmonic generation efficiency was correct. A simple method to predict the harmonic generation efficiency of a KDP crystal was provided. The method can also be applied to other harmonic generation crystals.

大孔径KDP（KH ₂ PO ₄高能固态激光器的最终光学组件中使用的晶体是实现惯性约束聚变的关键点之一。KDP晶体失谐角的变化是通过干涉仪和计算得出的。使用失谐角的变化来计算谐波产生效率。建立了基于小信号逼近理论的谐波产生效率理论预测模型。在实验中，使用了晶体离线调试系统来测量KDP晶体的实际谐波产生效率。将KDP晶体的预测谐波产生效率与实际效率进行了比较，得出理论上谐波产生效率的预测模型是正确的。提供了一种简单的方法来预测KDP晶体的谐波产生效率。该方法还可以应用于其他谐波产生晶体。