MRI: Development of a Mobile High-speed Dual Frequency Comb Spectroscopy User Facility

长期以来，激光一直是研究从内燃机、大气到生物学等系统中化学过程的首选工具。这些系统中的分子吸收特定颜色模式的光，因此可以通过在样品中照射不同颜色的光并量化出现的光模式来检测而不干扰过程。频率梳是一种激光源，它发出成千上万种不同的、紧密间隔的颜色的光。当在一个叫做“双频梳光谱”的特殊过程中与第二个频率梳进行干扰时，光源提供了无与伦比的潜力，可以结合颜色和时间分辨率来探测化学过程，这是任何其他仪器都无法做到的。这笔拨款将创建第一个移动频率梳用户设施——一个移动实验室，将频率梳技术直接带到全国各地的科学实验中。频率梳的新功能将使科学发现有益于人类健康、环境和国家安全，同时培训新一代频率梳激光工程师。基于宽带锁模频梳利用差频产生向中红外偏移，我们将构建第一台便携式、鲁棒的高速双梳光谱仪。双梳将能够同时测量中红外光谱区域的大部分，具有成千上万个单独的波长元素，时间分辨率低至10微秒。这将使在现场，微秒时间分辨率电影的化学动态过程揭开了前所未有的带宽和精度的众多物种。光谱仪将被整合到一个移动用户设施中，这将使以前从未接触过这种技术的研究人员能够使用双梳系统。我们已经在两个国家实验室和四所大学组建了一个由9个初始用户和项目组成的小组，他们将试点用户设施，以实现从化学动力学到显微镜等多个领域的科学突破。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Laser light has long been a preferred tool for studying chemical processes in systems ranging from combustion engines, to the atmosphere, to biology. Molecules in these systems absorb light in a specific pattern of colors, and thus can be detected without disturbing the process by shining different colors of light through the sample and quantifying the light pattern that emerges. The frequency comb is a laser source that emits hundreds of thousands of distinct, closely spaced colors of light. When interfered with a second frequency comb in a special process called "dual frequency comb spectroscopy", the light source offers unparalleled potential to probe chemical processes with a combination of color and time resolution that is not available with any other instrument. This grant will create the first mobile frequency comb user facility – a mobile laboratory that will bring frequency comb technology directly to scientific experiments across the country. The new capabilities of the frequency comb will enable scientific discovery that benefits human health, the environment, and national security while training a new generation of frequency comb laser engineers.We will build the first portable and robust high-speed dual-comb spectrometer based on broadband mode-locked frequency combs shifted to the mid-infrared using difference frequency generation. The dual-comb will be able to simultaneously measure across large portions of the mid-infrared spectral region with tens of thousands of individual wavelength elements and time resolution as low as 10 microseconds. This will enable in situ, microsecond time resolution movies of chemical dynamic processes unraveling across a multitude of species with unprecedented bandwidth and precision. The spectrometer will be incorporated into a mobile user facility that will put the dual comb system at the hands of researchers who have never before had access to this technology. We have assembled a group of 9 initial users and projects at two national labs and four universities that will pilot the user facility to enable scientific breakthroughs across multiple fields spanning chemical kinetics to microscopy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.