Abstract:Based on absorption principle, the paper calculated parameters of Beer-Lambert law to measure the light length. The paper analyzed Gaussian lineshape, Lorentzian lineshape and Voigt lineshape, and used the Voigt lineshape to fit the spectrum signal. The peak value of the Voigt lineshape, Lorentzian width and error function were also studied. The direct absorption spectroscopy of TDLAS was used to measure the oxygen absorption spectrum getting the fitted peak value. The light length was calculated as 66.55 cm through putting the peak value into the Beer-Lambert function. The value of comparative measurement was 66.04 cm, and the measurement accuracy was 0.78%. So, this method is suitable in light length measurement.
Key words:Light length measurement; Direct absorption spectroscopy; TDLAS; Beer-lambert law; peak value calculation
[1] Tudor I. Applied Physics Letters, 2005, 35(6): 26.
[2] Chang S, Jeffries B. AIAA Journal, 2010, 48(11): 547.
[3] Rieker B, Jonathan. Diode Laser Sensor for Gas Temperature and H<sub>2</sub>O Concentration in a Scramjet Combustor Using Wavelength Modulation Spectroscopy. New York: AIAA Joint Propulsion Conference & Exhibit, 2002. 589.
[4] Upschulte L, Miller F. AIAA Journal, 2003, 38(7): 89.
[5] Allen G. AIAA Journal, 2004, 31(6): 25.
[6] Sanders T, Mori Koichu. AIAA Journal, 2000, 27 (5): 62.
[7] David M Sonnenfroh. Diode Laser Sensors for Combustor and Aeroengine Emissions Testing Applications to CO,CO<sub>2</sub>,OH and NO. San Diego: AIAA Meeting Paper on Disc, 1996. 145.
[8] ZHOU Xiao-wei, LIU Hua-feng(周晓巍,刘华锋). High Power Laser and Particle Beams(强激光与粒子束), 2008, 5(6): 7.
[9] LI Fei, YU Xi-long, et al(李 飞,余西龙,等). Changsha: The Proceedings of Thirteenth National Conference on Shock and Shock Wave(长沙: 第十三届全国激波与激波管会议论文集), 2008. 78.
[10] Puerta J, Martin P. Applied Optics, 1981, 20 (2): 259.