title: Calibration-free wavelength modulated TDLAS under high absorbance conditions.
abstract: Currently, the method that uses a first-order Taylor series to approximate laser transmission has seriously affected the gas concentration measurement accuracy of tunable diode laser-absorption spectroscopy (TDLAS). This paper employs a second-order Taylor series to approximate laser transmission, and a high-precision second-order algorithm has been established that can determine the gas concentration directly. Then, this algorithm is used to test the NH₃ mole fraction in a cell with NH₃-Air mixtures. Experimental results show that the second-order algorithm not only effectively improves the measurement accuracy of gas concentration but also greatly broadens the scope of TDLAS.
authors: State Key Laboratory of Power Systems, Dept. of Thermal Engineering, Tsinghua University, Beijing 100084, China.
authors: Peng
authors: P
authors: Zhimin
authors: Ding
authors: D
authors: Yanjun
authors: Che
authors: C
authors: Lu
authors: Li
authors: L
authors: Xiaohang
authors: Zheng
authors: Z
authors: Kangjie