光场相机能够同时捕获光线的强度和方向信息，但由于成像传感器尺寸的限制，无法同时获得高空间和角度分辨率的光场图像。提出了一种联合傅里叶卷积和通道注意力的光场角度重建方法，通过使用稀疏光场图像4个边角位置的参考视图，可以间接地重建出密集光场图像。考虑到光场数据的内在4D结构，采用通道级密集快速傅里叶残差卷积块，在空域和频域对光场图像的空间和角度相关性进行建模，然后采用基于全局响应归一化的通道注意块，以实现通道间的自适应融合。此外，还提出了一种改进的视点加权间接合成方法，通过为每个参考视图分配一个置信图，为参考视图之间建立联系以合成更真实的新视图。实验结果表明，相比于现有先进的光场角度重建算法IRVAE，所提方法的重建光场图像质量在自然光场数据集30Scenes，Occlusion和Reflective上的平均PSNR分别提高了0.08，0.13和0.13 dB。所提方法在保证光场角度一致性的前提下取得了清晰的重建结果。

亚微米尺寸K₂SiF₆∶Mn⁴⁺荧光粉被认为是Micro-LED显示领域的变革性技术，但是小粒径K₂SiF₆∶Mn⁴⁺荧光粉的合成技术不成熟，难以实现亚微米尺度下的高效发光。因此，本文报道了一种亚微米级K₂SiF₆∶Mn⁴⁺荧光粉的沉淀合成新方法。经荧光光谱分析，该荧光粉在450 nm蓝光激发下展现出典型的Mn⁴⁺红色发光，其内量子效率高达94.9%。经扫描电子显微镜（SEM）观察，合成的荧光粉粒径分布在150 ~ 450 nm范围。该荧光粉具备良好的热猝灭性能，在443 K可保持室温发光强度的102%。将绿色荧光粉β-sialon∶Eu²⁺和K₂SiF₆∶Mn⁴⁺混合涂覆在蓝光芯片上制成白光LED，其色域覆盖范围达到133% NTSC，在驱动电流从10 mA增加到120 mA的情况下，色温波动~10%、显色指数波动~2%，总体性能保持稳定。本文将为亚微米尺寸K₂SiF₆∶Mn⁴⁺ 荧光粉的合成提供新的方法，以促进Micro-LED显示技术的进一步发展。

展开-合成技术常用于核辐射测量中的数字脉冲处理系统。本文提出了一种基于脉冲展开-合成技术的多项式数字脉冲成形方法，实现了平顶展宽尖峰脉冲成形算法。该算法首先将核脉冲信号展开为单位脉冲系列组合，然后合成冲激响应系统来形成尖峰形状，利用改进的平顶尖峰成形算法处理，并在幅值提取准确性、抗干扰能力和堆积识别等方面与传统的滤波成形算法进行比较分析。实验结果表明：针对¹³⁷Cs的γ特征峰，在相同的成形时间，平顶尖峰成形算法的能量分辨率为7.2%，优于梯形成形、三角成形和高斯成形算法，并且具有高计数率通过性能。因此，该方法可有效取代传统的脉冲成形方法，用于高精度、高计数率的γ能谱测量。

Radio frequency/microwave-directed energy sources using wide bandgap SiC photoconductive semiconductors have attracted much attention due to their unique advantages of high-power output and multi-parameter adjustable ability. Over the past several years, benefitting from the sustainable innovations in laser technology and the significant progress in materials technology, megawatt-class output power electrical pulses with a flexible frequency in the P and L microwave wavebands have been achieved by photoconductive semiconductor devices. Here, we mainly summarize and review the recent progress of the high-power photonic microwave generation based on the SiC photoconductive semiconductor devices in the linear modulation mode, including the mechanism, system architecture, critical technology, and experimental demonstration of the proposed high-power photonic microwave sources. The outlooks and challenges for the future of multi-channel power synthesis development of higher power photonic microwave using wide bandgap photoconductors are also discussed.

Manganese (Mn) doped cadmium sulphide (CdS) nanoparticles were synthesized using a chemical method. It was possible to decrease CdS : Mn particle size by increasing Mn concentration. Investigation techniques such as ultraviolet?visible (UV?Vis) absorption spectroscopy and photoluminescence (PL) spectroscopy were used to determine optical properties of CdS : Mn nanoparticles. Size quantization effect was observed in UV?Vis absorption spectra. Quantum efficiency for luminescence or the internal magnetic field strength was increased by doping CdS nanoparticles with Mn element. Orange emission was observed at wavelength ~630 nm due to ⁴T₁ → ⁶A₁ transition. Isolated Mn²⁺ ions arranged in tetrahedral coordination are mainly responsible for luminescence. Luminescence quenching and the effect of Mn doping on hyperfine interactions in the case of CdS nanoparticles were also discussed. The corresponding weight percentage of Mn element actually incorporated in doping process was determined by atomic absorption spectroscopy (AAS). Crystallinity was checked and the average size of nanoparticles was estimated using the X-ray diffraction (XRD) technique. CdS : Mn nanoparticles show ferromagnetism at room temperature. Transmission electron microscopy (TEM) images show spherical clusters of various sizes and selected area electron diffraction (SAED) patterns show the polycrystalline nature of the clusters. The electronic states of diluted magnetic semiconductors (DMS) of Ⅱ?Ⅵ group CdS nanoparticles give them great potential for applications due to quantum confinement. In this study, experimental results and discussions on these aspects have been given.

高能激光器性能直接决定了激光定向能的毁伤能力和打击射程，为此美国相继启动多项计划，以研制出高功率、高效、紧凑、轻量化，用于战场的坚固型激光器。2019年，启动了激光器定标放大计划（high energy laser scaling initiative，HELSI），制定出最新的国家级激光放大路线图。首先介绍美国HELSI计划的启动背景、研究内容和实施阶段，其次分析HELSI计划第一阶段300 kW的研究进展，最后评述HELSI计划进展的后续影响。综合分析可知，目前洛·马公司的光谱合成光纤激光器技术在第一阶段率先胜出，不仅获得陆军300 kW作战光源的订单，而且还首先获得HELSI计划第二阶段500 kW的研制合同；HELSI计划的进展，使导弹防御局（missile defense agency，MDA）重新重视用于拦截助推段弹道导弹的定向能**；HELSI计划支持了4种技术路线进行竞争发展，不过未来何种技术路线会最终胜出并部署在战场上，还需要加强先期论证，突破“技术迷雾”。