Eslami Jahromi Khalil, Nematollahi Mohammadreza, Pan Qing, Abbas Muhammad Ali, Cristescu Simona M, Harren Frans J M, Khodabakhsh Amir
Opt Express. 2020 Aug 31;28(18):26091-26101. doi: 10.1364/OE.396884.
We present a multi-species trace gas sensor based on a high-repetition-rate mid-infrared supercontinuum source, in combination with a 30 m multipass absorption cell, and a scanning grating spectrometer. The output of the spectrometer is demodulated by a digital lock-in amplifier, referenced to the repetition rate of the supercontinuum source. This improved the detection sensitivity of the system by a factor 5, as compared to direct baseband operation. The spectrometer provides a spectral coverage of 950 cm (between 2.85-3.90 µm) with a resolution of 2.5 cm in 100 ms. It can achieve noise equivalent detection limits in the order of 100 ppbv Hz for various hydrocarbons, alcohols, and aldehydes.
我们展示了一种基于高重复率中红外超连续谱源的多物种痕量气体传感器，该传感器与一个30米的多程吸收池以及一台扫描光栅光谱仪相结合。光谱仪的输出由一个数字锁相放大器解调，以超连续谱源的重复率为参考。与直接基带操作相比，这将系统的检测灵敏度提高了5倍。该光谱仪在100毫秒内提供950厘米（2.85 - 3.90微米之间）的光谱覆盖范围，分辨率为2.5厘米。对于各种碳氢化合物、醇类和醛类，它能够实现约100 ppbv Hz的噪声等效检测限。
