Fluorescence lifetime imaging can reveal the high-resolution structure of various biophysical and chemical parameters in a microenvironment quantitatively. However, the depth of imaging is generally limited to hundreds of micrometers due to aberration and light scattering in biological tissues. This paper introduces an iterative multi-photon adaptive compensation technique (IMPACT) into a two-photon fluorescence lifetime microscopy system to successfully overcome aberrations and multiple scattering problems in deep tissues. It shows that 400 correction modes can be achieved within 5 min, which was mainly limited by the frame rate of a spatial light modulator. This system was used for high-resolution imaging of mice brain tissue and live zebrafish, further verifying its superior performance in imaging quality and photon accumulation speed.

Three-dimensional (3D) nonlinear photonic crystals have received intensive interest as an ideal platform to study nonlinear wave interactions and explore their applications. Periodic fork-shaped gratings are extremely important in this context because they are capable of generating second-harmonic vortex beams from a fundamental Gaussian wave, which has versatile applications in optical trapping and materials engineering. However, previous studies mainly focused on the normal incidence of the fundamental Gaussian beam, resulting in symmetric emissions of the second-harmonic vortices. Here we present an experimental study on second-harmonic vortex generation in periodic fork-shaped gratings at oblique incidence, in comparison with the case of normal incidence. More quasi-phase-matching resonant wavelengths have been observed at oblique incidence, and the second-harmonic emissions become asymmetric against the incident beam. These results agree well with theoretic explanations. The oblique incidence of the fundamental wave is also used for the generation of second-harmonic Bessel beams with uniform azimuthal intensity distributions. Our study is important for a deeper understanding of nonlinear interactions in a 3D periodic medium. It also paves the way toward achieving high-quality structured beams at new frequencies, which is important for manipulation of the orbital angular momentum of light.

为了更好地实现多镜面大视场主动光学望远镜波前像差抑制、提升望远镜探测能力极限，本文基于望远镜视场边缘内置的错位型曲率传感器进行波前感知，并利用功率谱对波前感知结果进行分析，进而基于波前像差的空间频率特征进行调控。首先，基于复光场理论分析了非瞳面对系统波前调控的影响机理。其次，分析了本方法在多镜面大视场主动光学望远镜调控过程中的精度特性。再次，利用桌面实验对多镜面大视场主动光学望远镜调控的可行性进行了验证。最终，波前重建结果与理论波前相关性高于0.85。利用功率谱对各个视场的空间频率特性进行了分析，与单纯使用均方根对多镜面影响敏感度进行分析的方法相比，灵敏度提升了20%。

为了更好地对大口径分段望远镜进行集成检测与稳定性保持基准构建，本文提出一种大口径环形分段光学系统基准构建方法。首先，采用局部光瞳投射的方式实现光瞳对准映射；其次，利用微透镜阵列构建系统共焦空间基准；之后，基于环带整体调控模式，采用共焦与曲率半径联合分析，实现曲率半径与系统对准的共同调节；最后，利用白光干涉所形成的条纹包络进行粗共相探测，并利用通道光谱方法实现粗共相与精共相间的精度衔接，空间共焦基准定位精度优于125 μm，共相基准覆盖范围优于20 μm，精度优于0.5 μm，光谱基准不确定度优于5%。实现了不同时空特征扰动的分层次、多模态抑制，利用以上共基准原位测量新方法有效提升了光学系统原位计量检测精度并缩短了溯源链长度，增加了检测效率与准确度。

液晶波前校正器通常基于液晶显示器的工艺制备而成，因此其研制成本高、定制难度大。本文基于掩模光刻法制备液晶波前校正器，以实现液晶波前校正器的专用化、低成本研制。基于掩模光刻技术设计并制备了91像素的无源液晶驱动电极，并封装成液晶光学校正单元。设计并制备了驱动连接电路板，实现了液晶光学驱动单元和驱动电路板的匹配对接。对液晶波前校正器响应特性进行检测。结果显示，其相位调制量为5.5个波长，响应时间为224 ms。利用Zygo干涉仪进行球面波的产生和静态倾斜像差的校正。结果显示，其可以产生正负离焦波前，且对水平倾斜像差校正后，Zernike多项式中第一项的值从1.18降至0.16，校正幅度达86%，实现了像差的有效校正。本文的研究工作可为液晶波前校正器的研制提供新思路，进而拓宽其应用领域和场景。