Rey J M, Sigrist M W
ETH Zurich, Institute for Quantum Electronics, Laser Spectroscopy and Sensing Laboratory, Otto-Stern-Weg 1, Zurich CH-8093, Switzerland.
Photoacoustics. 2023 Jan 20;29:100455. doi: 10.1016/j.pacs.2023.100455. eCollection 2023 Feb.
A robust and simple sensing scheme utilizing a Mid-Infrared Light Emitting Diode (MIR-LED) and based on Differential Mode Excitation Photoacoustic (DME-PA) spectroscopy is presented. A MIR-LED light source in combination with optical correlation is used for simplicity and compactness. The sensing setup takes advantage of the non-linearity in the excitation of various acoustic modes in a cylindrical resonant photoacoustic cell to provide a high selectivity. The sensing device is tested using methane and hydrocarbon mixtures (propane, butane). The obtained limit of detection for methane is 25 ppm m. Using the presented DME-PA scheme, the derived gas concentration is hardly affected neither by intensity fluctuations of the light source nor by any microphone or electronics drifts. Furthermore, a considerably improved selectivity is obtained compared to conventional Non-Dispersive Infrared (NDIR) techniques.
提出了一种稳健且简单的传感方案，该方案利用中红外发光二极管（MIR-LED）并基于差模激发光声（DME-PA）光谱技术。为了实现简单性和紧凑性，采用了MIR-LED光源与光学相关性相结合的方式。该传感装置利用圆柱形共振光声池中各种声学模式激发的非线性特性，以实现高选择性。使用甲烷和碳氢化合物混合物（丙烷、丁烷）对传感装置进行了测试。所获得的甲烷检测限为25 ppm·m。使用所提出的DME-PA方案，推导得到的气体浓度几乎不受光源强度波动的影响，也不受任何麦克风或电子设备漂移的影响。此外，与传统的非色散红外（NDIR）技术相比，选择性有了显著提高。
