Draper Anthony D, Cole Ryan K, Makowiecki Amanda S, Mohr Jeffrey, Zdanowicz Andrew, Marchese Anthony, Hoghooghi Nazanin, Rieker Gregory B
Opt Express. 2019 Apr 15;27(8):10814-10825. doi: 10.1364/OE.27.010814.
We demonstrate fiber mode-locked dual-frequency comb spectroscopy for broadband, high-resolution measurements in a rapid compression machine (RCM). We apply an apodization technique to improve the short-term signal-to-noise-ratio (SNR), which enables broadband spectroscopy at combustion-relevant timescales. We measure the absorption on 24345 individual wavelength elements (comb teeth) between 5967 and 6133 cm at 704 µs time resolution during a 12 ms compression of a CH-N mixture. We discuss the effect of the apodization technique on the absorption spectra, and apply an identical effect to the spectral model during fitting to recover the mixture temperature. The fitted temperature is compared against an adiabatic model, and found to be in good agreement with expected trends. This work demonstrates the potential of DCS to be used as an in situ diagnostic tool for broadband, high-resolution measurements in engine-like environments.
我们展示了用于快速压缩机（RCM）中宽带、高分辨率测量的光纤锁模双频梳状光谱技术。我们应用了一种变迹技术来提高短期信噪比（SNR），这使得在与燃烧相关的时间尺度上进行宽带光谱测量成为可能。在对CH-N混合物进行12毫秒压缩期间，我们以704微秒的时间分辨率测量了5967至6133厘米之间24345个独立波长元素（梳齿）上的吸收情况。我们讨论了变迹技术对吸收光谱的影响，并在拟合过程中对光谱模型应用相同的影响以恢复混合物温度。将拟合温度与绝热模型进行比较，发现与预期趋势吻合良好。这项工作证明了双频梳状光谱技术在类似发动机环境中用作宽带、高分辨率原位诊断工具的潜力。
