Abstract：Cavity enhanced absorption spectroscopy (CEAS) is a new spectral technology that is based on the cavity ring down absorption spectroscopy. In the present paper, a DFB encapsulation narrow line width tunable diode laser (TDL) was used as the light source. At the center output, the TDL radiation wavelength was 1.573 μm, and an optical cavity, which consisted of two high reflectivity mirrors (near 1.573 μm, the mirror reflectivity was about 0.994%), was used as a sample cell. A wavemeter was used to record the accurate frequency of the laser radiation. In the experiment, the method of scanning the optical cavity to change the cavity mode was used, when the laser frequency was coincident with one of the cavity mode; the laser radiation was coupled into the optical cavity and the detector could receive the light signals that escaped the optical cavity. As a result, the absorption spectrum of carbon dioxide weak absorption at low pressure was obtained with an absorption intensity of 1.816×10-23 cm-1·(molecule·cm-2)-1 in a sample cell with a length of only 33.5 cm. An absorption sensitivity of about 3.62×10-7 cm-1 has been achieved. The experiment result indicated that the cavity enhanced absorption spectroscopy has the advantage of high sensivity, simple experimental setup, and easy operation.
[1] WANG Le-xin, ZHAO Zhi-min, YAO Hong-bing, CHEN Yu-ming, SHI Lei, GAO Yong(王乐新，赵志敏，姚红兵，陈玉明，石 磊，郜 勇). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2002, 22(6): 980. [2] LIU Yang-qing, YUAN Rong, ZHAO Hui-hui, BAI Gong, YANG Hui-fang(刘养清，苑 戎，赵慧辉，白 宫，杨慧芳). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2002, 22(5): 779. [3] O'Keefe Anthony, Deacon D A G. Review of Scientific Instruments, 1988, 59: 2544. [4] ZHAO Hong-tai, LIU Xiao-jun, ZHAN Ming-sheng(赵宏太，柳晓军，詹明生). Spectroscopy and Spectral Analysis(光谱学与光谱分析), 2001, 21: 284. [5] NIE Jin-song, ZHANG Wei-jun，YANG Yong, et al(聂劲松, 张为俊, 杨 顒, 等). Chinese Journal of Atomic and Molecular Physics(原子与分子物理学报), 2000, 17: 471. [6] Romanini D, Kachanov A A, Sadeghi N, et al. Chemical Physics Letters, 1997, 264(3-4): 316. [7] Romanini D, Kachanov A A, Stoeckel F. Chemical Physics Letters, 1997, 270: 538. [8] Romanini D, Kachanov A A, Stoeckel F. Chemical Physics Letters, 1997, 270: 546. [9] Engeln Richard, Berden Giel. Review of Scientific Instruments, 1998, 69: 3763. [10] Cheung A S C, Ma Tongmei, Chen Hongbing. Chemical Physics Letters, 2002, 353: 275. [11] Engeln Richard, Meijer Gerard. Review. Scientific Instruments, 1996. 67(8): 2708. [12] NIE Jin-song, ZHANG Wei-jun, YANG Yong, et al(聂劲松, 张为俊, 杨 顒, 等). Chinese Journal of Quantum Electronics(量子电子学报), 2001, 18(3): 217. [13] LIU Jie, LI Jian, YU Quan-xun(刘 杰, 李 健, 于全训). Chinese Journal of Laser(中国激光), 1997, 24(7): 591. [14] LI Jian, ZHUO Zhuang, WU Ling-an(李 健, 卓 壮, 吴令安). Journal of Optoelectronics·Laser(光电子·激光), 1995，6(6): 359.
