随着红外技术的不断发展，空间大口径红外光学元件的需求日益增长，其各项制造指标也逐渐接近可见光级光学元件的制造要求，由此对新型空间红外光学元件的加工和检测技术均提出了更高的挑战。针对大口径的高陡度超薄硅基红外透镜，提出了以超声铣磨-机器人研抛-离子束精抛为工艺链路的加工方案，改善了传统红外工艺路线存在的低效率、表面高频误差等问题。针对凸非球面轮廓检测中支撑引起的测试误差，在粗抛和精抛阶段分别采用了柔性缓冲支撑与三点强迫位移支撑方法，有效解决了大口径高陡度超薄透镜测试中的支撑变形问题。经过理论仿真与实验验证，证明该测试方法具有较好的一致性。通过改进的轮廓检测方法，实现了轮廓测试中支撑误差的准确分离，有效提升了加工的极限精度。最终大口径红外透镜凸非球面加工精度达RMS λ/50 （λ=632.8 nm），满足设计指标要求。

对于传统蜂窝夹芯结构的反射镜，因加工过程中网格效应的存在，反射镜的面板厚度和蜂窝尺寸之间彼此关联制约着，严重影响反射镜的轻量化设计。针对蜂窝夹芯结构的超轻ULE反射镜，提出了一种充气平衡式减小网格效应的加工方法，运用控制变量法，通过实验比对了正常加工和充气平衡式两种研抛状态下网格效应的变化。实验结果表明：当反射镜面形精度RMS达到1/10λ （λ=632.8 nm）以上时，正常加工的面形图存在明显的网格效应，而充气加工则没有，可见反射镜内部充气可有效平衡加工压力，使反射镜在加工过程中有筋区域和无筋区域的变形趋于一致，从而有效减小网格效应。

Cylindrical shockwaves inside polymethyl methacrylate (PMMA) generated simultaneously with two hemispherical shockwaves induced by a femtosecond Gaussian beam laser were investigated using an ultrafast pump–probe imaging technique. The evolutions of these three shockwaves with probe delay and incident pulse number have been systematically analyzed. The plasma intensity and filament length in the center of cylindrical shockwave both decayed with pulse number. Moreover, the self-focused filament moved downstream towards the output surface with an increased pulse number. The experimental results and mechanism illustrated that energy deposition was suppressed by a degraded nonlinear effect due to a pre-ablated structure in multi-pulse irradiation.

The dynamics of plasma and shockwave expansion during two femtosecond laser pulse ablation of fused silica are studied using a time-resolved shadowgraph imaging technique. The experimental results reveal that during the second pulse irradiation on the crater induced by the first pulse, the expansion of the plasma and shockwave is enhanced in the longitudinal direction. The plasma model and Fresnel diffraction theory are combined to calculate the laser intensity distribution by considering the change in surface morphology and transient material properties. The theoretical results show that after the free electron density induced by the rising edge of the pulse reaches the critical density, the originally transparent surface is transformed into a transient high-reflectivity surface (metallic state). Thus, the crater with a concave-lens-like morphology can tremendously reflect and refocus the latter part of the laser pulse, leading to a strong laser field with an intensity even higher than the incident intensity. This strong refocused laser pulse results in a stronger laser-induced air breakdown and enhances the subsequent expansion of the plasma and shockwave. In addition, similar shadowgraphs are also recorded in the single-pulse ablation of a concave microlens, providing experimental evidence for the enhancement mechanism.