Schaeffer R D, Sproul J C, O'Connell J, van Vloten C, Mantz A W
Appl Opt. 1989 May 1;28(9):1710-3. doi: 10.1364/AO.28.001710.
This paper describes the design and performance of a tunable diode laser system, incorporating a multipass absorption cell to allow determination of water concentration below 10 ppb and carbon dioxide concentration below 1 ppb in nitrogen semiconductor gas. The cell is used with a tunable Pb-salt diode laser spectrometer frequency locked to a first derivative error signal from an intense vibration-rotation molecular absorption line. Sample concentrations are monitored in the second derivative mode, and the system automatically compensates for laser intensity fluctuations. A flowing gas method is used to minimize adsorption/desorption effects from the sample cell walls.
本文描述了一种可调谐二极管激光系统的设计与性能，该系统包含一个多程吸收池，用于测定氮气半导体气体中低于10 ppb的水浓度和低于1 ppb的二氧化碳浓度。该吸收池与一台可调谐铅盐二极管激光光谱仪配合使用，该光谱仪的频率锁定在来自强振动 - 转动分子吸收线的一阶导数误差信号上。样品浓度在二阶导数模式下进行监测，并且该系统会自动补偿激光强度波动。采用流动气体法以最小化样品池壁的吸附/解吸效应。
