Miniaturized fiber-Bragg-grating (FBG) interrogators are of interest for applications in the areas where weight and size controlling is important, e.g., airplanes and aerospace or in-situ monitoring. An ultra-compact high-precision on-chip interrogator is proposed based on a tailored arrayed waveguide grating (AWG) on a silicon-on-insulator (SOI) platform. The on-chip interrogator enables continuous wavelength interrogation from 1 544 nm to 1 568 nm with the wavelength accuracy of less than 1 pm [the root-mean-square error (RMSE) is 0.73 pm] over the whole wavelength range. The chip loss is less than 5 dB. The 1 × 16 AWG is optimized to achieve a large bandwidth and a low noise level at each channel, and the FBG reflection peaks can be detected by multiple output channels of the AWG. The fabricated AWG is utilized to interrogate FBG sensors through the center of gravity (CoG) algorithm. The validation of an on-chip FBG interrogator that works with sub-picometer wavelength accuracy in a broad wavelength range shows large potential for applications in miniaturized fiber optic sensing systems.

水下爆炸气泡载荷是造成舰船结构整体损伤的主要原因, 研究水下爆炸气泡动态特性对水中兵器研发和舰船防护等方面至关重要。从水下爆炸气泡脉动的载荷特性出发, 综述了气泡动力学理论、实验和数值模拟三方面的研究进展, 总结气泡非球状坍缩运动过程、气泡与不同结构表面耦合作用以及自由场中多气泡耦合作用等问题的典型研究成果。在现有研究成果的基础上, 提出应建立综合考虑气泡内部因素和水中不同环境因素的气泡运动力学模型; 针对非理想炸药水中爆炸气泡运动特性规律开展更系统的实验研究; 进一步加强近边界条件下多气泡耦合过程的研究工作等建议。

Wettability is one of a solid surface’s fundamental physical and chemical properties, which involves a wide range of applications. Femtosecond laser microfabrication has many advantages compared to traditional laser processing. This technology has been successfully applied to control the wettability of material surfaces. This review systematically summarizes the recent progress of femtosecond laser microfabrication in the preparation of various superwetting surfaces. Inspired by nature, the superwettabilities such as superhydrophilicity, superhydrophobicity, superamphiphobicity, underwater superoleophobicity, underwater superaerophobicity, underwater superaerophilicity, slippery liquid-infused porous surface, underwater superpolymphobicity, and supermetalphobicity are obtained on different substrates by the combination of the femtosecond laser-induced micro/nanostructures and appropriate chemical composition. From the perspective of biomimetic preparation, we mainly focus the methods for constructing various kinds of superwetting surfaces by femtosecond laser and the relationship between different laser-induced superwettabilities. The special wettability of solid materials makes the femtosecond laser-functionalized surfaces have many practical applications. Finally, the significant challenges and prospects of this field (femtosecond laser-induced superwettability) are discussed.

Underwater transportation of bubbles and gases has essential applications in manipulating and using gas, but achieving this function at the microscopic level remains a significant challenge. Here, we report a strategy to self-transport gas in water along a laser-induced open superhydrophobic microchannel with a width less than 100 μm. The femtosecond laser can directly write superhydrophobic and underwater superaerophilic microgrooves on the polytetrafluoroethylene (PTFE) surfaces. In water, the single laser-induced microgroove and water medium generate a hollow microchannel. When the microchannel connects two superhydrophobic regions in water, the gas spontaneously travels from the small region to the large area along this hollow microchannel. Gas self-transportation can be extended to laser-drilled microholes through a thin PTFE sheet, which can even achieve anti-buoyancy unidirectional penetration. The gas can overcome the bubble’s buoyance and spontaneously travel downward. The Laplace pressure difference drives the processes of spontaneous gas transportation and unidirectional bubble passage. We believe the property of gas self-transportation in the femtosecond laser-structured open superhydrophobic and underwater superaerophilic microgrooves/microholes has significant potential applications related to manipulating underwater gas.

基于Pockels效应原理, 分别对交直流混合强电场传感器中的电光传感单元和电场调制机构进行了设计与测试。对电光传感单元结构进行合理设计, 选取并制备相关器件。搭建试验平台, 试验结果表明电光传感单元输入输出具有良好的线性度, 对电场波形的变化具有快速的响应且频率特性良好, 其性能满足测量调制后电场波形的需求。利用电光传感单元和电场调制机构组建传感器, 并测量了交直流混合强电场响应。