Vol.2 No.3 (July 2012)
Theoretical Derivation and Experimental Research of Harmonic Signals Based on TDLAS
In this paper, we derived the expression for the instantaneous intensity based on numerical simulation and practical experiments in tunable diode laser absorption spectroscopy, and determined the new expression of the harmonic signals in wavelength modulation spectroscopy, then we analyzed the influence to the harmonic signals caused by the phase shifts between the detected and reference signals. The transition of CO2 at 6527.64 cm–1 was selected for the practical experiments, and the experimental results indicated that, the amplitude of laser intensity modulation was invariant during the scanning process, which did not change with the average scanning laser intensity. What’s more, the amplitude and phase of the harmonic signals were influenced by the phase shifts between the detected and reference signals, which cannot be ignored in gas concentration and temperature measurements.
车璐 , 丁艳军 , 彭志敏 (2012) TDLAS技术中谐波信号的理论推导与实验研究。 应用物理， 2， 92-97. doi: 10.12677/APP.2012.23016
 S. Wagner, B. T. Fisher, J. W. Fleming, et al. TDLAS-based in situ measurement of absolute acetylene concentrations in lami- nar 2D diffusion flames. Proceedings of the Combustion Insti- tute, 2009, 32(1): 839-846.
 A. Farooq, J. B. Jeffries and R. K. Hanson. CO2 concentration and temperature sensor for combustion gases using di-ode-laser absorption near 2.7 μm. Applied Physics B, 2008, 90(3-4): 619- 628.
 J. T. C. Liu, J. B. Jeffries and R. K. Hanson. Wave-length modu- lation absorption spectroscopy with 2f detection using multi- plexed diode lasers for rapid temperature measurements in gase- ous flows. Applied Physics B, 2004, 78: 503-511.
 H. Li, G. B. Rieker, X. Liu, et al. Extension of wavelength- modulation spectros-copy to large modulation depth for diode laser absorption measure-ments in high-pressure gases. Applied Optics, 2006, 45(5): 1052-1061.
 陈东, 刘文清, 阚瑞峰等. 基于可调谐半导体激光吸收光谱的瓦斯监测方法研究[J]. 光学技术, 2006, 32(4): 598-603.
 阐瑞峰, 刘文清, 张玉钧等. 基于可调谐激光吸收光谱的大气甲烷监测仪[J]. 光学学报, 2006, 26(1): 67-70.
 J. Reid, D. Labrie. Second harmonic detection with tunable diode la-sers-comparison of experiment and theory. Applied Phys- ics B, 1981, 26: 203-210.
 T. D. Cai, H. Jia, G. S. Wang, et al. A sensor for measurements of temperature and water concentration using a single tunable di- ode laser near 1.4 um. Sensors and Actuators A, 2009, 152(1): 5-12.
 王健, 黄伟, 顾海涛等. 可调谐二极管激光吸收光谱法测量气体温度[J]. 光学学报, 2007, 27(9): 1639-1646.
 A. Farooq, J. B. Jeffries and R. K. Hanson. Sensitive detection of tem-perature behind reflected shock waves using wavelength modulation spectroscopy of CO2 near 2.7 μm. Applied Physics B, 2009, 96: 161-173.
 G. B. Rieker, J. B. Jeffries, R. K. Hanson, et al. Diode laser- based detection of combustor instabilities with application to a scramjet engine. Proceedings of the Combustion Institute, 2009, 32(2): 831-838.
 G. B. Rieker, J. B. Jeffries and R. K. Hanson. Calibra-tion-free wavelength modulation spectroscopy for measurements of gas temperature and concentration in harsh environments. Applied Optics, 2009, 48(29): 5546-5560.
 F. Wang, K. F. Cen, N. Li, et al. Simul-taneous measurement on gas concentration and particle mass concen-tration by tunable diode laser. Flow Measurement and Instrumentation, 2010, 21(3): 382-387.
 L. Che, Y. J. Ding and Z. M. Peng. Re-search on the influences of temperature, concentration and pressure uncertainties on meas- urement results of wavelength modulation spec-troscopy. Chinese Physics Letters, 2012, 29(6): Article ID: 067801.
 Z. M. Peng, Y. J. Ding, L. Che, et al. Odd harmonics with wave- length modulation spectroscopy for recovering gas ab-sorbance shape. Optics Express, 2012, 20(11): 11976-11985.