Laser processing with high-power ultrashort pulses, which promises high precision and efficiency, is an emerging new tool for material structuring. High repetition rate ultrafast laser highlighting with a higher degree of freedom in its burst mode is believed to be able to create micro/nanostructures with even more variety, which is promising for electrochemical applications. We employ a homemade high repetition rate ultrafast fiber laser for structuring metal nickel (Ni) and thus preparing electrocatalysts for hydrogen evolution reaction (HER) for the first time, we believe. Different processing parameters are designed to create three groups of samples with different micro/nanostructures. The various micro/nanostructures not only increase the surface area of the Ni electrode but also regulate local electric field and help discharge hydrogen bubbles, which offer more favorable conditions for HER. All groups of the laser-structured Ni exhibit enhanced electrocatalytic activity for HER in the alkaline solution. Electrochemical measurements demonstrate that the overpotential at 10 mA cm ^{- 2} can be decreased as much as 182 mV compared with the overpotential of the untreated Ni (-457 mV versus RHE).

In this work, we present a high-power, high-repetition-rate, all-fiber femtosecond laser system operating at 1.5 $\unicode{x3bc}$ m. This all-fiber laser system can deliver femtosecond pulses at a fundamental repetition rate of 10.6 GHz with an average output power of 106.4 W – the highest average power reported so far from an all-fiber femtosecond laser at 1.5 $\unicode{x3bc}$ m, to the best of our knowledge. By utilizing the soliton-effect-based pulse compression effect with optimized pre-chirping dispersion, the amplified pulses are compressed to 239 fs in an all-fiber configuration. Empowered by such a high-power ultrafast fiber laser system, we further explore the nonlinear interaction among transverse modes LP₀₁, LP₁₁ and LP₂₁ that are expected to potentially exist in fiber laser systems using large-mode-area fibers. The intermodal modulational instability is theoretically investigated and subsequently identified in our experiments. Such a high-power all-fiber ultrafast laser without bulky free-space optics is anticipated to be a promising laser source for applications that specifically require compact and robust operation.

Lead halide perovskite materials exhibit excellent scintillation performance, which, however, suffer from serious stability and toxicity problems. In contrast, the heavy metal-free anti-perovskite materials [ MX₄ ] XA₃ (A = alkali metal; M = transition metal; X = Cl, Br, I), a class of electron-inverted perovskite derivatives, exhibit robust structural and photophysical stability. Here, we design and prepare a lead-free [ MnBr₄ ] BrCs₃ anti-perovskite nanocrystal (NC)-embedded glass for efficient X-ray-excited luminescence with high-resolution X-ray imaging with a spatial resolution of 19.1 lp mm ^{- 1}. Due to the unique crystal structure and the protection of the glass matrix, the Cs₃MnBr₅ NC-embedded glass exhibits excellent X-ray irradiation stability, thermal stability, and water resistance. These merits enable the demonstration of real-time and durable X-ray radiography based on the developed glassy composite. This work could stimulate the research and development of novel metal halide anti-perovskite materials and open a new path for future development in the field of high-resolution and ultrastable X-ray imaging.

多维（多模）激光是突破单模激光技术瓶颈的重要途径，有望推动多学科交叉与创新发展。不同于传统的单模激光，多维激光具有光场结构复杂、可调控参数多等特点，其性能调控面临诸多挑战。近年来，随着人工智能的兴起，机器学习等智能调控技术被广泛用于光学系统性能的优化，推动了智能光学及相关学科的快速发展，为多维激光的智能调控提供了新思路。从激光谐振腔内部和外部调控两方面，介绍了智能调控技术在激光调控领域中的研究进展，并展望了智能调控多维激光技术在光学微操控、激光微加工和空间光通信等领域中的应用前景。

In two-photon microscopy, low illumination powers on samples and a high signal-to-noise ratio (SNR) of the excitation laser are highly desired for alleviating the problems of photobleaching and phototoxicity, as well as providing clean backgrounds for images. However, the high-repetition-rate Ti:sapphire laser and the low-SNR Raman-shift lasers fall short of meeting these demands, especially when used for deep penetrations. Here, we demonstrate a 937-nm laser frequency-doubled from an all-fiber mode-locked laser at 1.8 μm with a low repetition rate of ∼9 MHz and a high SNR of 74 dB. We showcase two-photon excitations with low illumination powers on multiple types of biological tissues, including fluorescence imaging of mouse brain neurons labeled with green and yellow fluorescence proteins (GFP and YFP), DiI-stained and GFP-labeled blood vessels, Alexa Fluor 488/568-stained mouse kidney, and second-harmonic-generation imaging of the mouse skull, leg, and tail. We achieve a penetration depth in mouse brain tissues up to 620 μm with an illumination power as low as ∼10 mW, and, even for the DiI dye with an extremely low excitation efficiency of 3.3%, the penetration depth is still up to 530 μm, indicating that the low-repetition-rate source works efficiently for a wide range of dyes with a fixed excitation wavelength. The low-repetition-rate and high-SNR excitation source holds great potential for biological investigations, such as in vivo deep-tissue imaging.

随着激光玻璃及光功能玻璃应用需求的快速增长，对光功能玻璃在光学性能和机械性能的要求越加趋向于多元化，而玻璃结构的不确定性和组分连续可调的特性阻碍了新型光功能玻璃材料的快速研发，为了摆脱传统的“试错型”设计模式，缩短玻璃材料开发的成本与周期，提升玻璃材料设计与制备过程的可预测性，“材料基因组计划”应运而生。“材料基因组计划”将高性能计算、数据和实验相结合，根据材料的组分对材料的特性进行定量地准确预测，从而指导新型材料的设计与开发。本文归纳并总结了目前应用于激光玻璃及光功能玻璃领域中的“材料基因工程”的不同理论与建模流程，分为基于物理定义推导的物理性方法、对实验数据进行统计分析的经验性方法、理论和经验相结合的理论-经验结合法。在此基础上，从激光玻璃和光功能玻璃材料出发，重点介绍“材料基因工程”在该领域的最新进展，并对未来的发展方向进行了展望。

单频光纤激光器在激光**、激光雷达、空间激光通信、相干光通信、高精度光谱测量、引力波探测等领域有着广泛的应用前景,受到了研究者的极大关注。从1.0,1.5,2.0 μm三种典型工作波段进行归类,综述了单频光纤激光器的国内外研究现状,内容涵盖了单频光纤激光产生、噪声抑制、线宽压窄、连续与脉冲单频激光放大等技术。此外,结合了本课题组在单频光纤激光器方面的研究工作,着重介绍了基于单振荡器和主振荡功率放大器结构的单频光纤激光器近年来的研究进展,并展望了单频光纤激光器的未来发展方向。

In this paper, a technique combining cascaded energy-transfer pumping (CEP) method and master-oscillator power-amplifier (MOPA) configuration is proposed for power scaling of 1.6-μm-band single-frequency fiber lasers (SFFLs), where the Er3+ ion has a limited gain. The CEP technique is fulfilled by coupling a primary signal light at 1.6 μm and a C-band auxiliary laser. The numerical model of the fiber amplifier with the CEP technique reveals that the energy transfer process involves the pump competition and the in-band particle transition between the signal and auxiliary lights. Moreover, for the signal emission, the population density in the upper level is enhanced, and the effective population inversion is achieved thanks to the CEP. A single-frequency MOPA laser at 1603 nm with an output power of 52.6 W and an improved slope efficiency of 30.4% is experimentally obtained through the CEP technique. Besides, a laser linewidth of 5.2 kHz and a signal-to-auxiliary laser ratio of 60.7 dB are obtained at the maximum output power. The proposed technique is anticipated to be promising for increasing the slope efficiency and power scaling for fiber lasers operating at L band.

Nd³⁺-doped fiber lasers at around 900 nm based on the ⁴F_3/2 → ⁴I_9/2 transition have obtained much research attention since they can be used as the laser sources for generating pure blue fiber lasers through the frequency doubling. Here, an all-fiber laser at 915 nm was realized by polarization-maintaining Nd³⁺-doped silica fiber. A net gain per unit length of up to 1.0 dB/cm at 915 nm was obtained from a 4.5 cm fiber, which to our best knowledge is the highest gain coefficient reported in this kind of silica fiber. The optical-to-optical conversion efficiency varies with the active fiber length and the reflectivity of the output fiber Bragg grating (FBG), presenting an optimal value of 5.3% at 5.1 cm fiber length and 70% reflectivity of the low reflection FBG. Additionally, the linear distributed Bragg reflector short cavity was constructed to explore its potential in realizing single-frequency 915 nm fiber laser. The measurement result of longitudinal-mode properties shows it is still multi-longitudinal mode laser operation with 40 mm laser cavity. These results indicate that the Nd³⁺-doped silica fiber could be used to realize all-fiber laser at 915 nm, which presents potential to be the seed source of high-power fiber laser.