CAREER: Ultrafast Time/Frequency Domain Coherent Anti-Stokes Raman Spectroscopy for Combustion and Plasma Systems

智能优点：燃烧和等离子系统的优化对于从清洁发电到材料加工的广泛应用非常重要。这项研究的目的是通过开发和使用一种新的激光光谱方法，即超快时/频域相干反斯托克斯拉曼光谱，显著提高对新型燃烧和等离子体系统中非平衡气相化学的认识和理解。这项技术有可能克服传统激光诊断方法的许多缺点，因为它能够在时间尺度上同时表征依赖于温度和压力的能量转移过程，从而能够解决分子碰撞、单物种和多物种内的振动和旋转能级以及共振和非共振时间动力学。初步数据表明，这些过程的测量速度可以比以前的光谱方法快至少一百倍，从而允许以前所未有的细节解析许多实际设备中的瞬变。为捕捉超快激光与物质相互作用的基本光物理而开发和验证随时间变化的理论模型将与实验创新的发展并行进行，并在许多情况下指导实验创新的发展。更广泛的影响：这项研究的广泛影响将在一定程度上通过促进对气相化学的详细理解来实现，这对于应对清洁能源和制造业当前和未来的挑战至关重要。有益于社会的应用包括开发表面(或气固)化学的化学和分子动力学模拟、高压煤/生物质气化、燃烧装置的减排、替代燃料的催化升级和利用、用于边界流动控制的电子放电、等离子体辅助点火/燃烧、纳米管的等离子体合成以及用于太阳能转换的等离子体沉积硅合金。例如，均质充气压缩点火和富氧燃料燃烧等策略需要非常规的操作条件，需要实验方法来帮助开发和验证在一定温度和压力范围内的化学动力学和能量传递过程模型。通过这项工作获得的科学知识将通过学术出版物以及与学术界、工业界和国家实验室的合作广泛传播。综合研究和教育计划包括通过科学和工程女性方案扩大联合研究和教育活动，以及由国家科学基金会赞助的本科生研究经验和教师研究经验。研究生将获得在实验室和课堂上教授和指导本科生的经验，以及通过他们已经试行的名为“光速工程”的新项目激励K-12学生。通过这项工作获得的知识还将用于研究生和本科生参加的高级燃烧课程，以及通过在工程学院设立能源系统辅修课程来扩大课程。

Intellectual Merit: Optimization of combustion and plasma systems is important for a wide range of applications, from clean power generation to materials processing. The objective of this research is to significantly enhance the knowledge and understanding of non-equilibrium gas-phase chemistry in novel combustion and plasma systems through the development and use of a new laser spectroscopic approach known as ultrafast time/frequency domain coherent anti-Stokes Raman spectroscopy. This technique has the potential to overcome many of the shortcomings of conventional laser diagnostic approaches by enabling simultaneous characterization of temperature- and pressure-dependent energy transfer processes on a time scale that can resolve molecular collisions, vibrational and rotational energy levels within single and multiple species, as well as resonant and non-resonant time dynamics. Preliminary data indicate that these processes can be studied at measurement rates that are at least one hundred times faster than previous spectroscopic approaches, allowing transients in many practical devices to be resolved with unprecedented detail. The development and validation of a time-dependent theoretical model to capture the fundamental photophysics of ultrafast laser-matter interactions will take place in parallel with, and in many cases, guide the development of experimental innovations. Broader Impact: The broad impact of this research will be achieved, in part, by advancing the detailed understanding of gas-phase chemistry that is important for meeting current and future challenges in clean energy and manufacturing. Applications that benefit society include the development of chemical and molecular dynamics simulations of surface (or gas-solid) chemistry, high-pressure coal/biomass gasification, emissions reduction in combustion devices, catalytic upgrading and utilization of alternative fuels, electric discharges for boundary flow control, plasma-assisted ignition/combustion, plasma synthesis of nanotubes, and plasma deposition of silicon alloys for solar energy conversion. Strategies such as homogeneous charge compression ignition and oxy-fuel combustion, for example, invoke unconventional operating conditions, and experimental methods are required to help develop and validate models of chemical kinetics and energy transfer processes for a range of temperatures and pressures. The scientific knowledge gained through this work will be disseminated broadly through scholarly publications and collaboration with academia, industry, and national laboratories. The integrated research and education plan includes expansion of joint research and education activities through the Program for Women in Science and Engineering, as well as NSF sponsored Research Experiences for Undergraduates and Research Experiences for Teachers. Graduate students will gain experience in teaching and mentoring undergraduate students both in the laboratory and classroom, as well as inspiring k-12 students through a new program they have already piloted called "Engineering at the Speed of Light." The knowledge gained through this work will also be used for an advanced combustion course attended by graduate and undergraduate students, as well as expansion of curricula through the establishment of an Energy Systems minor in the College of Engineering.