实时便捷的pH检测对于环境监测和医学诊断等领域具有重要应用价值。本文通过溶胶?凝胶法制备了一种比率荧光毛细管pH传感器。该传感器以2.8?羟基芘?1，3，6?三磺酸三钠盐（8?hydroxy?pyrene?1，3，6?trisulfonate，HPTS）作为pH敏感的荧光探针，利用HPTS与十六烷基三甲基溴化铵（hexadecyl trimethyl ammonium bromide，CTAB）结合形成HPTS?IP离子对，然后将离子对分散于溶胶?凝胶中，并将其固定于毛细管内壁即制得比率荧光毛细管pH传感器。该传感器利用HPTS在双激发带下的发射强度比值实现比率荧光检测，当pH从5.0上升至8.0时，HPTS的荧光强度比率随pH值增加逐渐增强，pKa值为6.95，通过分析HPTS的比率荧光强度变化可间接监测pH波动。该传感器具有较好的pH敏感性、稳定性和可逆性，且可快速、灵活、便捷地进行实际操作，在环境保护和生物医学领域的pH监测分析方面拥有良好的应用前景。

The discharged capillary plasma channel has been extensively studied as a high-gradient particle acceleration and transmission medium. A novel measurement method of plasma channel density profiles has been employed, where the role of plasma channels guiding the advantages of lasers has shown strong appeal. Here, we have studied the high-order transverse plasma density profile distribution using a channel-guided laser, and made detailed measurements of its evolution under various parameters. The paraxial wave equation in a plasma channel with high-order density profile components is analyzed, and the approximate propagation process based on the Gaussian profile laser is obtained on this basis, which agrees well with the simulation under phase conditions. In the experiments, by measuring the integrated transverse laser intensities at the outlet of the channels, the radial quartic density profiles of the plasma channels have been obtained. By precisely synchronizing the detection laser pulses and the plasma channels at various moments, the reconstructed density profile shows an evolution from the radial quartic profile to the quasi-parabolic profile, and the high-order component is indicated as an exponential decline tendency over time. Factors affecting the evolution rate were investigated by varying the incentive source and capillary parameters. It can be found that the discharge voltages and currents are positive factors quickening the evolution, while the electron-ion heating, capillary radii and pressures are negative ones. One plausible explanation is that quartic profile contributions may be linked to plasma heating. This work helps one to understand the mechanisms of the formation, the evolutions of the guiding channel electron-density profiles and their dependences on the external controllable parameters. It provides support and reflection for physical research on discharged capillary plasma and optimizing plasma channels in various applications.

面向毛细管微反应器固相状态检测需求，提出了一种激发微管腔回音壁谐振的光纤楔形端面耦合器。建立了光纤楔形端面耦合模型，通过理论研究楔形端面与微管腔倏逝场耦合原理，仿真模拟楔形端面光场分布情况，并分析了光纤楔形端面与微管腔耦合谐振的光谱特征。研磨制备耦合器件，搭建实验系统进行实验验证。实验采集到洛伦兹凹谷型耦合谐振谱，与理论仿真分析相一致。谐振谱1563.074 nm波长附近的自由光谱范围约为1.734 nm，Q值约为6.15×10³。所提出的光纤楔形端面耦合器具有较好的器件鲁棒性，耦合谐振结构简单，易于器件集成和小型化。

Advances in the generation of the shortest optical laser pulses down to the sub-cycle regime promise to break new ground in ultrafast science. In this work, we theoretically demonstrate the potential scaling capabilities of soliton self-compression in hollow capillary fibers with a decreasing pressure gradient to generate near-infrared sub-cycle pulses in very different dispersion and nonlinearity landscapes. Independently of input pulse, gas and fiber choices, we present a simple and general route to find the optimal self-compression parameters which result in high-quality pulses. The use of a decreasing pressure gradient naturally favors the self-compression process, resulting in shorter and cleaner sub-cycle pulses, and an improvement in the robustness of the setup when compared to the traditional constant pressure approach.