高时空分辨可视化技术是脑科学研究的重要工具。荧光显微成像技术在特异性、多样性、图像对比度和时空分辨率等方面具有显著优势，但由于光在组织中的穿透深度有限，无创的荧光成像难以在活体水平获取深层脑区神经血管单元的高分辨结构和功能信息。因此，在脑科学研究中，荧光内窥显微成像技术受到越来越多研究者的青睐。得益于相关科学技术的发展，内窥镜探头在保持高性能的同时，实现了小型化并提供了更大的灵活性，可以植入活体大脑的不同深度处，开展特定深层脑区的功能调控研究。本综述介绍了基于梯度折射率透镜和单根多模光纤这两种探头的植入式荧光内窥显微成像技术及其发展和迭代进程，概述了它们在高分辨活体脑成像研究中的应用，以及在临床神经外科手术中的初步探索性应用。最后，展望了荧光内窥脑成像技术未来的发展前景。

为探究不同铟(In)组分InxGa1-xN势垒对绿光激光二极管光电性能的影响，本文采用SiLENSe(simulator of light emitters based on nitride semiconductors)仿真软件对一系列具有不同In组分InxGa1-xN势垒的激光二极管进行研究，结果发现InxGa1-xN势垒中In组分最佳值为3%，此时结构的斜率效率最高，内部光学损耗最低，光学限制因子最大，性能最优。在具有In0.03Ga0.97N势垒的多量子阱结构基础上，设计了一种组分阶梯(composition step-graded， CSG)InGaN势垒多量子阱结构，提高了激光二极管的斜率效率和电光转换效率，增加了光场限制能力。仿真结果表明，当注入电流为120 mA时，具有CSG InGaN势垒的多量子阱结构，电光转换效率从17.7%提高至19.9%，斜率效率从1.09 mW/mA增加到1.14 mW/mA，光学限制因子从1.58%增加到1.62%。本文的研究为制备高功率GaN基绿光激光二极管提供了理论指导和数据支撑。

创新性地提出了一种基于高Q值轴向渐变型空芯微腔的高灵敏流速传感器，实现了微压状态下微腔回音壁模式共振光场对流体的直接检测。首先，利用流体动力学和有限元算法理论分析了轴向渐变型空芯微腔的流速和光场特性。其次，通过熔融拉锥和气压控制法制备了高Q值（Q>10⁷）轴向渐变型空芯微腔，利用五维高精度位移平台实现微腔与微纳光纤的高精度、低损耗耦合。实验测试并研究了不同尺寸、不同耦合位置时微腔回音壁模式共振光谱的流速传感特性，获得的最大流速灵敏度达0.27 pm/（μL/min），流速分辨率为1.43 μL/min。该传感器具有较高的重复性和实时性，在高灵敏度流体检测、水质检测等领域具有潜在应用价值。

无粘结裂缝的产生可以被视为宏观裂缝发展的标志。为探究地震作用对全级配混凝土裂缝行为特征的影响，采用一种无粘结裂缝的识别模型，以数字图像相关技术作为试件裂缝扩展的监测手段，对不同加载速率(0.000 1 mm/s、0.001 0 mm/s、0.010 0 mm/s)的全级配混凝土试件进行三点弯曲试验，考虑全级配混凝土裂缝扩展的率相关性。结果表明：对于不同加载时间间隔内的全级配混凝土试件，峰值前后均会产生无粘结裂缝，说明达到峰值荷载时预制裂缝处已发生开裂；试件的破坏主要集中在荷载加载至峰值荷载的50%以后；相同条件下，加载速率越慢，无粘结裂缝出现的阶段越早，随着加载速率增大，裂缝呈现细而长的特征。

The miniaturized femtosecond laser in near infrared-II region is the core equipment of three-photon microscopy. In this paper, we design a compact and robust illumination source that emits dual-color linearly polarized light for three-photon microscopy. Based on an all-polarization-maintaining passive mode-locked fiber laser, we shift the center wavelength of the pulses to the 1.7μm band utilizing cascade Raman effect, thereby generate dual-wavelength pulses. To enhance clarity, the two wavelengths are separated through the graded-index multimode fiber. Then we obtain the dual-pulse sequences with 1639.4nm and 1683.7nm wavelengths, 920fs pulse duration, and 23.75MHz pulse repetition rate. The average power of the signal is 53.64mW, corresponding to a single pulse energy of 2.25nJ. This illumination source can be further amplified and compressed for three-photon fluorescence imaging, especially dual-color three-photon fluorescence imaging, making it an ideal option for biomedical applications.

高功率可见光至近红外波段的超连续谱光源在光电对抗、光学相干层析成像和高光谱激光雷达等方面具有广泛的应用前景。最近几年，涌现了一些用于产生高功率超连续谱光源的新方法，推动了高功率超连续谱光源的进一步发展。本文从主振荡功率放大结构、随机光纤激光器结构以及多路非相干合成这三种用于高功率超连续谱产生的主流方案出发，着重介绍了近年来有代表性的高功率可见光至近红外波段超连续谱光源的研究进展，并综合分析了这三种方案的优缺点以及未来的发展潜力。

Bio-inspired porous metallic scaffolds have tremendous potential to be used as artificial bone substitutes. In this work, a radially graded lattice structure (RGLS), which mimics the structures of natural human bones, was designed and processed by laser powder bed fusion of martensitic Ti-rich TiNi powder. The asymmetric tension-compression behaviour, where the compressive strength is significantly higher than the tensile strength, is observed in this Ti-rich TiNi material, which echoes the mechanical behaviour of bones. The morphologies, mechanical properties, deformation behaviour, and biological compatibility of RGLS samples were characterised and compared with those in the uniform lattice structure. Both the uniform and RGLS samples achieve a relative density higher than 99%. The graded porosities and pore sizes in the RGLS range from 40%-80% and 330-805 μm, respectively, from the centre to the edge. The chemical etching has significantly removed the harmful partially-melted residual powder particles on the lattice struts. The compressive yield strength of RGLS is 71.5 MPa, much higher than that of the uniform sample (46.5 MPa), despite having a similar relative density of about 46%. The calculated Gibson-Ashby equation and the deformation behaviour simulation by finite element suggest that the dense outer regions with high load-bearing capability could sustain high applied stress, improving the overall strength of RGLS significantly. The cell proliferation study suggests better biological compatibility of the RGLS than the uniform structures. The findings highlight a novel strategy to improve the performance of additively manufactured artificial implants by bio-inspiration.