Miniaturization and integration of photoacoustic detection
Miniaturization and integration of photoacoustic detection
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DOI：
10.1063/1.1489493
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发表时间：
2002-08-01
影响因子：
3.2
通讯作者：
Schmidt, MA
中科院分区：
文献类型：
--
作者：
Firebaugh, SL;Jensen, KF;Schmidt, MA
光声光谱是一种吸收光谱技术，目前用于低水平气体检测和催化剂表征。这是一种在中尺度分析系统中很有前途的化学分析技术，因为它的检测下限具有良好的小型化特点。这项工作集中在光声光谱的尺度性质，以及在氮气环境中丙烷的气相光声检测的小型化。利用传输线类比对检测系统进行了建模，并进行了实验验证。该模型考虑了声泄漏和吸收饱和的影响。这两种现象降低了光声探测器的性能，必须加以控制才能实现光声系统的定标优势。用于验证该模型的微型黄铜电池使用助听器麦克风和3.39微米的机械斩波He-Ne激光器的光激励，通过光纤传输到电池中。这些电池能够在氮气中检测到10ppm的丙烷(信号水平类似于1pA/W)。我们还描述了由微加工形成的小型化光声系统的发展。在这种情况下，检测膜的压力驱动偏转是光学测量的。这些系统表明，由于吸收饱和和气体声学性质的变化，光声检测可能不适合气体浓度变化较大的系统。然而，光声光谱学是一种很有前途的技术，用于分析微型化学体系中的稀薄混合物。(C)2002年美国物理研究所。
Photoacoustic spectroscopy is an absorption spectroscopy technique that is currently used for low-level gas detection and catalyst characterization. It is a promising technique for chemical analysis in mesoscale analysis systems because the detection limit scales favorably with miniaturization. This work focuses on the scaling properties of photoacoustic spectroscopy, and on the miniaturization of gas-phase photoacoustic detection of propane in a nitrogen ambient. The detection system is modeled with a transmission line analogy, which is verified experimentally. The model includes the effects of acoustic leaks and absorption saturation. These two phenomena degrade the performance of the photoacoustic detector and must be controlled to realize the scaling advantages of photoacoustic systems. The miniature brass cells used to verify the model employ hearing aid microphones and optical excitation from a mechanically chopped, 3.39 mum He-Ne laser, transmitted into the cells with an optical fiber. These cells are able to detect 10 ppm of propane in nitrogen (a signal level of similar to1 Pa/W). We also describe the development of a miniaturized photoacoustic system formed by microfabrication. In this case, the pressure-driven deflection of the detection membrane is measured optically. These systems show that photoacoustic detection may be inappropriate for systems with large variations in gas concentration because of absorption saturation and changing gas acoustic properties. Nevertheless, photoacoustic spectroscopy is a promising technique for the analysis of dilute mixtures in miniature chemical systems. (C) 2002 American Institute of Physics.