Measurement of Oxygen Concentration Using Multimode Diode Laser Absorption Spectroscopy
GAO Guang-zhen1, 2, CAI Ting-dong2*, HU Bo1, JIA Tian-jun1
1. Department of Optical Engineering, Binzhou University, Binzhou 256603, China 2. College of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
Abstract：Tunable diode laser absorption spectroscopy (TDLAS) is a widely used technique for high sensitivity, good selectivity and fast response. It is widely used in environment monitoring, industrial process control and biomedical sensing. In order to overcome the drawbacks of TDLAS including high cost, poor stability and center wavelength shift problem. A multi-mode diode laser system based on correlation spectroscopy and wavelength modulation spectroscopy (TMDL-COSPEC-WMS) was used to measure O2 concentration near 760nm at the 1%～30% range of near room temperature. During the experiment, the light is splitter into two beams, respectively through the sample and measuring cell, two receiving optical signal collection containing gas concentration information sent back stage treatment, invert the oxygen concentration through correlation and ratio between measured signal and reference signal, the correlation spectroscopy harmonic detection technique is used to improve the stability of the system and the signal to noise ratio. The result showed that, there was a good linear relationship between the measured oxygen concentration and the actual concentration value. A detection limit of 280 pmm﹒m in the 1 atmospheric which approved of the same sample. A continuous measurement for oxygen with the standard deviation of 0.056% in ambient air during approximately 30minutes confirms the stability and the capability of the system. The design of the system includes soft and hardware can meet the needs of oxygen online monitoring. The experimental device is simple and easy to use, easy to complex environment application.
[1] Sandstrom L, Malmberg D. Spectrochim. Acta A, 2002, 58(11): 2449. [2] Burke C S, Moore J P, Wencel D A, et al. Journal of Biomedical Optics, 2008, 13(1): 014027. [3] Moos R, Menesklou W, Schreiner H J, et al. Sensors and Actuators B, 2000, 67(1-2): 178. [4] Lee J H. Journal of Materials Science, 2003, 38(21): 4247. [5] Shao J, Gao X, Deng L, et al. Chinese Physics Letter, 2004, 21(10): 1908. [6] LIU Wen-qing, CUI Zhi-cheng, LIU Jian-guo, et al(刘文清, 崔志成, 刘建国, 等). Chinese Journal of Quantum Electronics(量子电子学报), 2004, 21(4): 202. [7] Lou X, Somesfalean G, Chen B, et al. Applied Optics, 2009, 48(5): 990. [8] Lou X, Somesfalean G, Xu F, et al. Applied Physics B, 2008, 93(2): 671. [9] Lou X, Somesfalean G, Chen B, et al. Optics Letters, 2010, 35(11): 1749. [10] Cai T, Wang G, Jia H, et al. Sensor and Actuator A: Physics，2009, 152(1): 5. [11] Li H, Farooq A, Rieker G B, et al. Applied Physics B, 2007, 89(2-3): 407.
