Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, CB2 3RA Cambridge, UK.
Appl Spectrosc. 2009 Dec;63(12):1389-95. doi: 10.1366/000370209790108987.
In this paper we demonstrate how broadband cavity enhanced absorption spectroscopy (CEAS) with supercontinuum (SC) radiation in the near-infrared spectral range can be used as a sensitive, multiplexed, and simple tool to probe gas-phase species in high-temperature environments. Near-infrared SC radiation is generated by pumping a standard single-mode fiber with a picosecond fiber laser. Standard low reflectivity mirrors are used for the cavity and an optical spectrum analyzer is used for the detection of gas-phase species in combustion. The method is demonstrated by measuring flame generated H(2)O in the 1500 to 1550 nm region and room-temperature CO(2) between 1520 nm and 1660 nm. The broadband nature of the technique permits hundreds of rotational features to be recorded, giving good potential to unravel complex, convoluted spectra. We discuss practical issues concerning the implementation of the technique and present a straightforward method for calibration of the CEAS system via a cavity ringdown measurement. Despite the large spectral variation of SC radiation from pulse to pulse, it is shown that SC sources can offer good stability for CEAS where a large number of SC pulses are typically averaged.
本文展示了如何在近红外光谱范围内使用宽带腔增强吸收光谱（CEAS）与超连续（SC）辐射，将其作为一种灵敏、多路复用和简单的工具，用于探测高温环境中的气相物质。近红外 SC 辐射是通过用皮秒光纤激光器对标准单模光纤进行泵浦产生的。标准低反射率镜子用于腔，并且使用光学频谱分析仪来探测燃烧中的气相物质。该方法通过测量在 1500 至 1550nm 区域产生的火焰中的 H(2)O 和在 1520nm 至 1660nm 之间的室温 CO(2)来进行演示。该技术的宽带特性允许记录数百个转动特征，为解析复杂、扭曲的光谱提供了良好的潜力。我们讨论了实施该技术的实际问题，并通过腔衰荡测量提出了一种简单的 CEAS 系统校准方法。尽管 SC 辐射的光谱随脉冲而发生很大变化，但事实证明，SC 源可为 CEAS 提供良好的稳定性，其中通常会平均大量的 SC 脉冲。
