高效、高平均功率固体纳秒脉冲激光器在光电对抗、激光雷达、材料改性、激光加工等诸多领域发挥着越来越重要的作用，然而目前大多数纳秒级高平均功率激光器采用Yb:YAG或掺Nd材料作为增益介质，材料的高饱和通量或低储能密度会导致激光器放大链路复杂，体积庞大。研究比较了一种更适合作为高平均功率、高脉冲能量激光器增益介质的无序石榴石晶体Yb:CNGG，研究了有源反射镜结构中Yb:CNGG的多程增益特性，分析了放大过程并建立了多程放大模型，在一定的泵浦条件下优化了晶体参数以实现更好的储能。开展了双程放大实验，在15 kW/cm²的泵浦功率密度下得到了1.53倍的增益。对比Yb:CNGG晶体与Yb:YAG晶体的多程放大能力，在相同的晶体参数和泵浦条件下，在入射能量1 mJ时Yb:CNGG可实现2.11 J的脉冲能量输出，优于Yb:YAG晶体1.41 J的能量输出。

The orbital angular momentum (OAM) of light has been implemented as an information carrier in OAM holography. Holographic information can be multiplexed in theoretical unbounded OAM channels, promoting the applications of optically addressable dynamic display and high-security optical encryption. However, the frame-rate of the dynamic extraction of the information reconstruction process in OAM holography is physically determined by the switching speed of the incident OAM states, which is currently below 30 Hz limited by refreshing rate of the phase-modulation spatial light modulator (SLM). Here, based on a cross convolution with the spatial frequency of the OAM-multiplexing hologram, the spatial frequencies of an elaborately-designed amplitude distribution, namely amplitude decoding key, has been adopted for the extraction of three-dimensional holographic information encoded in a specific OAM information channel. We experimentally demonstrated a dynamic extraction frame rate of 100 Hz from an OAM multiplexing hologram with 10 information channels indicated by individual OAM values from –50 to 50. The new concept of cross convolution theorem can even provide the potential of parallel reproduction and distribution of information encoded in many OAM channels at various positions which boosts the capacity of information processing far beyond the traditional decoding methods. Thus, our results provide a holographic paradigm for high-speed 3D information processing, paving an unprecedented way to achieve the high-capacity short-range optical communication system.

在固体激光脉冲放大器中，再生放大器具有增益高、光束质量好以及结构简单等优点，得到了广泛的关注和应用。经过几十年的不断发展，再生放大器已经能够实现数百mJ脉冲能量以及数kW均值功率的稳定输出。增益材料特性、腔型结构、泵浦能力、热效应、元器件性能等诸多方面都会影响再生放大器的输出特性，其中增益材料特性是最根本的因素。由于特性不同，基于不同增益材料体系的再生放大器在结构和功能上都会有较大的差异。基于不同的材料体系，介绍了各类体系下的再生放大器在发展过程中遇到的关键共性问题，以及几类典型的再生放大器及其特点。讨论了再生放大器未来的发展趋势。

The use of low-coherence light is expected to be one of the effective ways to suppress or even eliminate the laser–plasma instabilities that arise in attempts to achieve inertial confinement fusion. In this paper, a review of low-coherence high-power laser drivers and related key techniques is first presented. Work at typical low-coherence laser facilities, including Gekko XII, PHEBUS, Pharos III, and Kanal-2 is described. The many key techniques that are used in the research and development of low-coherence laser drivers are described and analyzed, including low-coherence source generation, amplification, harmonic conversion, and beam smoothing of low-coherence light. Then, recent progress achieved by our group in research on a broadband low-coherence laser driver is presented. During the development of our low-coherence high-power laser facility, we have proposed and implemented many key techniques for working with low-coherence light, including source generation, efficient amplification and propagation, harmonic conversion, beam smoothing, and precise beam control. Based on a series of technological breakthroughs, a kilojoule low-coherence laser driver named Kunwu with a coherence time of only 300 fs has been built, and the first round of physical experiments has been completed. This high-power laser facility provides not only a demonstration and verification platform for key techniques and system integration of a low-coherence laser driver, but also a new type of experimental platform for research into, for example, high-energy-density physics and, in particular, laser–plasma interactions.