利用量子级联激光光声光谱法检测氨。

Ammonia detection by using quantum-cascade laser photoacoustic spectroscopy.

作者信息

Filho Milton B, da Silva Marcelo G, Sthel Marcelo S, Schramm Delson U, Vargas Helion, Miklós Andras, Hess Peter

机构信息

Laboratório de Ciências Físicas, Centro de Ciência e Technologia, Universidade Estadual do Norte Fluminense, Campos dos Goytacazes-RJ, Brazil.

出版信息

Appl Opt. 2006 Jul 10;45(20):4966-71. doi: 10.1364/ao.45.004966.

DOI:10.1364/ao.45.004966

PMID:16807606

Abstract

A pulsed quantum-cascade distributed-feedback laser, temperature tunable from -41 degrees C to +31.6 degrees C, and a resonant differential photoacoustic detector are used to measure trace-gas concentrations to as low as 66 parts per 10(9) by volume (ppbv) ammonia at a low laser power of 2 mW. Good agreement between the experimental spectrum and the simulated HITRAN spectrum of NH3 is found in the spectral range between 1046 and 1052 cm(-1). A detection limit of 30 ppbv ammonia at a signal-to-noise ratio of 1 was obtained with the quantum-cascade laser (QCL) photoacoustic (PA) setup. Concentration changes of approximately 50 ppbv were detectable with this compact and versatile QCL-based PA detection system. The performance of the PA detector, characterized by the product of the incident laser power and the minimum detectable absorption coefficient, was 4.7 x 10-9 W cm(-1).

摘要

一台脉冲量子级联分布反馈激光器，温度可在-41摄氏度至+31.6摄氏度之间调节，以及一个共振差分光声探测器，用于在2毫瓦的低激光功率下测量痕量气体浓度，低至体积分数为66×10⁻⁹（ppbv）的氨。在1046至1052厘米⁻¹的光谱范围内，实验光谱与NH₃的模拟HITRAN光谱之间发现了良好的一致性。使用量子级联激光（QCL）光声（PA）装置，在信噪比为1时获得了30 ppbv氨的检测限。使用这种紧凑且通用的基于QCL的PA检测系统可检测到约50 ppbv的浓度变化。PA探测器的性能以入射激光功率与最小可检测吸收系数的乘积为特征，为4.7×10⁻⁹瓦·厘米⁻¹。