Ultrafast Velocity Measurement of Shock Wave using Microwave Photonic Velocimetry

该奖项支持一种新型传感方式的基础研究，即微波光子测速(MPV)。在冲击波实验中，测速仪测量的是冲击波在发展、传播和衰减时的速度。这提供了有关冲击波行为的关键信息。该项目的目标是支持对超快冲击波速度的现场和实时测量，超快冲击波的传播速度约为几十公里/S。这将使含能材料的研究成为可能，并最终导致安全得多的工业工作场所，在那里可能会发生爆炸。能够测量超快冲击波的坚固而准确的测速技术是一个突出的技术挑战，限制了我们对冲击波物理和化学的理解。如果成功，MPV技术将大大扩展我们对材料在各种物理条件(温度、压力、浓度等)下爆炸能力的了解，从而填补这一空白。因此，本项目所追求的MPV突破将在预防灾害和改善危险环境中的安全方面产生重大的社会效益。特别是，预计MPV将成为安全处理和储存非理想(边界)爆炸物的有利工具。这些材料通常被认为是安全的，但在某些条件下可能会对工作场所构成致命威胁。具体的研究目标包括理解和表征MPV的概念，研究新的信号处理方法，并使用大规模室外爆炸测试来验证这种新的传感模式。直接的结果是对MPV概念的基本了解、实施和演示。主要创新之处包括：1)创新地利用微波和光波之间的相互作用，创造出精确、坚固和低成本的速度计；2)将光学频率梳技术创新地整合到MPV系统中，以精确分离在频域中测量的元素；3)新型MPV探头与集成的梯度折射率光纤(GIF)准直器，显著提高了MPV的性能；4)新型信号处理算法，可智能重建爆炸事件的速度历史轮廓；5)增强的多路复用能力，可实现同时、多探头的冲击波速度测量。

This award supports fundamental research on a novel sensing modality, namely, microwave photonic velocimetry (MPV). In shock wave experimentation, velocimetry is the measurement of the speed of a shock wave as it develops, propagates, and fades. This provides critical information on shock wave behavior. The goal of this project is to support the measurement of the velocity of ultrafast shock waves, traveling at speeds in the order of several tens of km/s, in-situ and in real-time. This will enable the study of energetic materials, and eventually lead to much safer industrial workplaces where explosions may pose a hazard. Robust and accurate velocimetry that can measure ultrafast shock waves is an outstanding technical challenge that limits our understanding of shock wave physics and chemistry. If successful, the MPV technology will fill this void by substantially expanding our knowledge of materials' ability to detonate under a wide variety of physical conditions (temperature, pressure, concentration, etc.). Thus, breakthroughs in MPV as pursued in this project, will have significant societal benefits in preventing disasters and improving safety in hazardous environments. In particular, MPV is anticipated to be an enabling tool in the safe handling and storage of non-ideal (borderline) explosives. These are materials that are conventionally rated as safe, but may become a deadly threat in workplaces under certain conditions. Specific research objectives include understanding and characterizing the MPV concept, investigating novel signal processing methodologies, and validating this novel sensing modality using large-scale, outdoor detonation tests. The direct outcome is the fundamental knowledge, implementation, and demonstration of the MPV concept. Key innovations include: 1) the innovative use of interactions between microwave and optical waves, enabling the creation of a precise, robust, and low-cost velocimetery, 2) the innovative integration of optical frequency comb technologies in the MPV system to precisely separate elements measured in the frequency-domain, 3) the novel MPV probe with integrated graded index fiber (GIF) collimator, which significantly enhances MPV's performance, 4) a novel signal processing algorithm that intelligently reconstructs the velocity history profiles of explosion events, and 5) enhanced multiplexing capability allowing for simultaneous, multi-probe shock wave velocity measurement.