激光致声技术可以将空气中的激光信号转化为水下的水声信号，将两种最佳信道高效地结合起来，从而解决空中-水下跨界通信问题。为了提高激光致声跨界通信的保密性和光声转化效率，采用了数值计算方法对不同条件下，激光在海面三维散射特性和透射特性进行了研究。首先，为了提高仿真计算的准确性，建立了三维激光海面散射场的数学模型。其次，采用数值计算方法求解三维激光海面散射的表面积分方程，并根据入射光波的特点，对入射界面进行强、弱区划分，以提高计算效率。最后，通过室内模拟试验对仿真结果进行了验证。研究结果表明，入射角度对于汽化激光致声通信的保密性和效率有着重要的影响，为后续的系统设计和相关应用研究提供了有意义的参考。

This work presents a brief review of our recent research on an antiresonant mechanism named core antiresonant reflection (CARR), which leads to a broadband terahertz (THz) spectrum output with periodic dips at resonant frequencies after its transmission along a hollow-core tubular structure (e.g., a paper tube). The CARR theory relies only on parameters of the tube core (e.g., the inner diameter) rather than the cladding, thus being distinct from existing principles such as the traditional antiresonant reflection inside optical waveguides (ARROWs). We demonstrate that diverse tubular structures, including cylindrical, polyhedral, spiral, meshy, and notched hollow tubes with either transparent or opaque cladding materials, as well as a thick-walled hole, could indeed become CARR-type resonators. Based on this CARR effect, we also perform various applications, such as pressure sensing with paper-folded THz cavities, force/magnetism-driven chiral polarization modulations, and single-pulse measurements of the angular dispersion of THz beams. In future studies, the proposed CARR method promises to support breakthroughs in multiple fields by means of being extended to more kinds of tubular entities for enhancing their interactions with light waves in an antiresonance manner.

白光发光二极管（LED）在固态照明中应用广泛，其中蓝色荧光粉因发挥十分重要的作用而成为当前研究的热点。本文采用高温固相法合成了KYBaSi₂O₇∶Bi³⁺蓝色荧光粉，研究了材料的发光特性。结果显示，在370 nm光激发下，KYBaSi₂O₇∶Bi³⁺呈现出覆盖380~600 nm、主峰位于418 nm的不对称宽带发射；Bi³⁺离子的发光存在浓度猝灭现象；温度升高时，材料表现出了较好的温度稳定性，在400 K时仍能保持64%的初始强度。此外，将其和商用荧光粉以及370 nm的近紫外芯片结合制成了白光LED，其色坐标为（0.368 2，0.398 1），色温为4 463 K，表明利用该材料可以实现近紫外基白光LEDs。

基于中红外光谱分析技术对浓香型白酒原酒中总酸及己酸乙酯的关键指标含量进行检测分析, 采用标准正态变换(SNV)方法对数据进行预处理, 结合组合间隔偏最小二乘波段选择法(SiPLS)及遗传算法(GA)对各指标的特征吸收波长进行筛选, 最终采用偏最小二乘法(PLS)建立分析模型, 通过决定系数R²、 预测标准偏差(RMSEP)、 性能和标准差之比(RPD)以及实际生产的独立测试样品对所建模型效果进行评价, 探索中红外光谱分析技术结合波段筛选用于白酒原酒关键指标的定量分析效果。 结果表明: 采用中红外全光谱397~4 000 cm^-1波段所建模型效果并不理想, 总酸及己酸乙酯模型的RMSEP值分别达到0.156及0.981, R²仅有0.666及0.453, RPD值为1.731及1.213, 代表模型整体的相关拟合效果并不理想, 预测误差较大, 无法应用于实际生产。 而采用GA在SiPLS波段优化基础上进一步进行特征变量筛选后, 所建模型效果有了非常显著的提升, 总酸及己酸乙酯两项指标的GA-SiPLS模型均体现出了较高的预测精度, R²分别提升到了0.993及0.997, RMSEP值分别降低到0.023及0.077, RPD值提升至11.739及15.455, 变量数也分别从935个降低到55及40个, 在保留关键信息变量, 体现原酒中总酸及己酸乙酯指标特征吸收的同时, 有效减轻了模型的复杂程度, 同时提高了模型运算速度及预测效果, 充分体现了波段筛选对于中红外光谱分析技术应用于白酒原酒关键指标定量分析的重要性, 也说明了中红外光谱技术结合波段筛选在白酒品质控制及原酒成分分析中的巨大潜力。 考虑到白酒成分复杂, 大部分关键品质指标含量相对较低, 而中红外吸收区域的基频吸收强度具有比倍频、 合频吸收强数十倍的特点, 中红外光谱可能比其余光谱技术更适用于白酒液体样品的快速分析, 为白酒酿造过程的品质控制提供技术借鉴, 同时为酒类品质的快速分析方法开拓提供新的思路。

Real-time and high-resolution imaging is demonstrated based on field trial detection of a non-cooperative target using a photonics-based inverse synthetic aperture radar (ISAR). By photonic generation and de-chirping of broadband linear frequency modulation signals, the radar can achieve a high range resolution thanks to the large instantaneous bandwidth (8 GHz at the K band), as well as real-time ISAR imaging using low-speed analog-to-digital conversion (25 MSa/s). A small-size unmanned aerial vehicle is employed as the non-cooperative target, and ISAR imaging is realized with a resolution far better than those achieved by the previously reported photonics-based ISARs. The capability for real-time ISAR imaging is also verified with an imaging frame rate of 25 fps. These results validate that the photonics-based radar is feasible in practical real-time and high-resolution ISAR imaging applications.

We report a simple Nd:YAG laser that emits radially polarized beam with helical wavefront. The laser cavity consists of a piece of laser crystal and a plane output coupler, and there is no additional polarization component inside it. The pump light is converted into annular profile through de-focal coupling into a multi-mode fiber. For the continuous-wave (CW) operation, the laser emits radially polarized vortex beam, and it is observed that the helical wavefront of the laser beam is switched from right handedness to left handedness when the output coupler is tilted slightly. For the Q-switched operation under the insertion of a Cr4+:YAG saturable absorber inside the cavity, we obtain radially polarized outputs with left-handedness helical wavefront. By tilting the laser crystal slightly, the laser output switches to azimuthal polarization at pump power larger than 4.5 W and left-handedness helical wavefront of laser beam is preserved.