可调谐半导体激光吸收光谱技术(TDLAS)是利用半导体激光器的波长调谐特性, 扫描待测气体特征吸收线, 从而获得待测气体的浓度信息。基于可调谐半导体激光吸收光谱的自平衡检测方法能够有效地消除激光器光强波动等共模噪声和其他同性干扰的影响。实验表明自平衡检测方法可以获得较理想的结果, 检测限低于体积比1.2×10-6, 与直接吸收光谱法相比降低了一个数量级。自平衡检测电路简单, 自带的电子增益补偿机制能够自动进行平衡探测, 该方法不用加信号调制和锁相放大器, 直接探测待测气体的吸收光谱, 从而降低成本, 减小系统装置体积, 易于集成为便携式痕量气体检测仪。

Tunable diode laser absorption spectroscopy (TDLAS) is a new method to detect target gas concentration, based on the wavelength tunable characteristic of diode laser, by obtaining the absorption spectra in the characteristic absorption region. Autobalanced detection based on TDLAS can effectively eliminate laser intensity noise and other common mode noise. The experiment shows that autobalanced detection could obtain ideal result. The detection limit is below volume ratio 1.2×10-6, and the precision is improved by one order of magnitude contrast to the direct absorption spectroscopy. This autobalanced detection method gains absorption spectra directly, and without signal modulation and lock-in amplifiers, so the excess laser noise is avoided. The noise-cancelling circuit is simple, and it could reduce the cost and system fit volume, and make the system apt to integrate.