Overview: Since the groundbreaking discovery of gravitational waves, the scientific community has fervently pursued the exploration of low-frequency gravitational waves to glean deeper insights into the cosmos. The inherent limitations of ground-based conditions, however, pose formidable challenges for detectors in capturing gravitational waves below the 1 Hz threshold. Consequently, the imperative has shifted toward the deployment of space-based gravitational wave detectors as the paramount solution for effective low-frequency gravitational wave detection. At the crux of space-based gravitational wave detection lies the pivotal role of spaceborne telescopes. Given the expansive transmission distances spanning magnitudes of 10⁹ m between celestial constellations, the demand for nanoradian-level precision in telescope pointing accuracy becomes non-negotiable. The concomitant necessity for high-precision measurements and calibration emerges as a prerequisite for achieving the exacting standards of pointing accuracy in spaceborne telescopes dedicated to gravitational wave detection. To ameliorate the deleterious effects of pointing deviations on gravitational wave detection, this study strategically optimizes key parameters, including microlens structures, detector selection, and algorithmic frameworks, thereby achieving a breakthrough in high-precision pointing deviation measurements. Leveraging a low-density microlens array with extended sub-aperture focal lengths enhances the spatial scale of the light spot within each sub-aperture. This, coupled with detectors boasting a high signal-to-noise ratio, synergistically elevates the pointing detection accuracy of each discrete lens. Moreover, the paper introduces an innovative, Hartmann principle-based methodology for high-precision pointing deviation measurements, deploying a spatially reused paradigm across multiple sub-apertures. By aggregating measurement results from diverse sub-apertures, the approach effectively mitigates the influence of assorted random errors on measurement accuracy, thereby markedly enhancing the precision of pointing deviation measurements. Illustrating the efficacy of these methodologies, the paper exemplifies their application within the ambit of the "Tianqin Plan" for space-based gravitational wave detection. Employing numerical simulations and factoring in the design parameters of the Hartmann sensor, the study performs a meticulous analysis of pointing deviation measurement accuracy. Comparative analysis between single sub-aperture and sub-aperture correlation reuse technologies reveals a compelling enhancement in measurement accuracy, approximating a sevenfold improvement with the latter. The pointing deviation measurement accuracy achieved through sub-aperture correlation reuse technology is quantified at approximately 18.81 nanoradians. Considering the optical magnification inherent in spaceborne telescopes, estimated at around 30 times, the resultant pointing deviation measurement accuracy reaches an impressive 0.62 nanoradians. This design precision significantly surpasses the stipulated 1 nanoradian accuracy requirement for ground-based gravitational wave pointing deviation measurements. As a prudential measure, the proposed design incorporates a substantial margin to accommodate potential accuracy diminution attributable to external perturbations during empirical testing.

为了实现可见光波段多路不同波长激光的周期性闭环校正，设计了一种具有光束指向和位置偏差独立监测与调节的激光合束系统。首先，根据系统的应用需求，提出了合束系统的设计指标与整体合束方案。然后，在合束方案的基础上，建立了合束系统的光束控制模型，并通过数值仿真得到了合束系统光束控制的解算方法。闭环合束系统通过光束指向和位置监测装置分别实现合束激光指向偏差与位置偏差的独立监测，并根据监测结果进行光束调节装置控制量的解算；进而通过两维摆镜和一维平移台分别实现光束指向和位置偏差的独立高效调节。最后，采用两路不同波长的激光束，配合光束监测与调节装置，搭建了闭环合束模拟实验平台，对周期性闭环合束系统的合束效果进行了验证。实验结果表明：在长时间的工作过程中，两路激光均实现了与基准光路的精密合束，合束指向精度优于±7 μrad，位置精度优于±0.84 mm。本研究所组建的激光合束系统不仅具有合束精度高、校正速度快、光路扩展性强的优势，而且可实现激光束的周期性闭环校正，能够有效保证合束激光的长期工作稳定性。

结合理论分析与实验测试，研究了在可见光脉冲输入条件下频率以及第二片微通道板与阳极之间电势差对微通道板光电倍增管动态范围的影响。研究结果表明：随着信号光脉冲频率的增大，微通道板壁面电荷补充不充分致使阳极输出偏离线性，并逐渐趋于饱和。当输入可见光脉冲宽度为50 ns，频率为500 Hz时，阳极的最大线性输出达到2 V（即40 mA）；当输入光频率增加到1 000 Hz，阳极输出在1 V（即20 mA）时线性偏离程度达到10%以上；当输入光频率增加到5 000 Hz，阳极输出在0.3 V（即6 mA）时线性偏离程度达到约15%。随着第二片微通道板与阳极之间电势差的增大，阳极最大线性输出电压呈现波动性变化而非与其呈线性关系。当第二片微通道板与阳极之间的电势差在200 V左右时，阳极线性输出电压达到峰值，随着电势差不断增大，阳极线性输出电压开始出现波动，在电势差为500 V左右时达到第二个峰值，这主要是由于极板间电场强度与空间电荷效应共同作用的结果。该研究可为提升微通道板光电倍增管的动态范围提供指导，便于其应用于强辐射脉冲测量、激光通信等领域。

为了获得稳定性更好、能量更大的准分子激光输出脉冲，对合束方式提高输出脉冲能量稳定性的可行性进行了理论推导、模拟实验以及合束实验研究。从理论推导得知，当激光输出脉冲能量符合正态分布时，多台激光器合束可以降低输出能量相对标准差。对三台输出脉冲能量分布特性符合正态分布的准分子激光器进行合束模拟实验研究，每台输出脉冲能量平均值约为153 mJ，脉冲能量相对标准差约为1%。两台准分子激光器合束时得到输出脉冲能量平均值为305 mJ、能量相对标准差为0.7%的准分子激光脉冲。三台准分子激光器合束时可以得到输出能量平均值为458 mJ、能量相对标准差为0.6%的准分子激光脉冲。使用两台准分子激光器进行三次实际合束实验，其中两台准分子激光器三次合束分别输出能量平均值约为355、350、330 mJ，相对标准差为1.3%、1.2%、1.4%的激光脉冲；三次合束后分别得到能量平均值为687、694、646 mJ，相对标准差为0.86%、0.79%、0.83%的激光脉冲。模拟实验以及合束实验都表明，合束后的能量相对标准差均小于单台能量相对标准差，即合束提高准分子输出脉冲的稳定性。因此，当单台准分子激光输出脉冲能量符合正态分布且平均能量相当时，多台合束可以有效提高激光输出脉冲的能量稳定性。

针对现有中心偏差测量方法中测量精度低、透镜姿态调整人为干扰大的问题，提出一种差动共焦透镜中心偏自动测量方法。该方法通过差动共焦定焦技术，依据差动共焦轴向光强响应曲线的过零点精确对应被测镜特征点这一特性，实现对被测镜猫眼点及共焦点的精准定位；通过高精度气浮转轴驱动被测镜旋转，用位移传感器、圆光栅记录被测镜的位置信息，结合五维位姿自动调整机构，实现对被测镜姿态的高精度校正，消除姿态偏差，提高测量精度；最终，搭建了激光差动共焦透镜中心偏自动测量系统，实现了透镜中心偏的高精度自动测量。实验结果表明：透镜中心偏的测量精度可达0.41%，测量重复性优于100 nm。与现有的人工单次测量相比，该方法的测量重复性较好、随机误差小、测量精度高，为高精度透镜中心偏自动测量提供了一种技术途径。

光切片图像的质量与使用的重构算法直接相关，传统的均方根算法虽然简洁，但在原始图像信噪比和条纹对比度不高时重构效果不佳，得到的三维重建结果并不理想。针对该问题，提出一种去背景和去卷积相结合的光切片方法。与传统均方根算法相比，该方法能有效减少残留条纹，提高微小细节的可见性。实验搭建了一套基于数字微镜器件的结构照明显微系统，以小鼠肾脏细胞、牛肺动脉内皮细胞等为样品进行了光切片实验。实验结果表明，该方法能获得更好的光切片和三维成像效果。