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Proceedings Paper

Evaluating the thermal stability of multi-pass cells' effective optical path length using optical frequency domain reflectometer
Author(s): Hong Gao; Xiuhan Cao; Jinyi Li; Zhenhui Du
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Paper Abstract

Multi-pass cells (MPCs) are commonly used to improve the sensitivity for trace gas detection using spectroscopy technologies. The determination of Effective Optical Path Length (EOPL) of a MPC is very important and challenging in applications which aim at absolute measurements. It is well-known that the temperature changing will exercise some influence on the MPCs’ spatial structure, however, measurements of the influence haven’t been reported which might due to the limitation of measuring method. In this paper, we used a direct high-precision measuring method with Optical Frequency Domain Reflectometer (OFDR) to evaluate the thermal stability of a multi-pass cell. To simulate the environment with a large range of temperature changing, this paper gave a series of experiments by setting the temperature control unit in system from 25 to 175 degree Celsius, and the MPC’s EOPL was measured simultaneously for the investigation of temperature response. The results showed that the effective optical path length increase monotonically along with the variation of the temperature, and the rising rate is 0.5 mm/ºC with the total length of about 3 meters which should be pay attention to when the ultra-high accuracy results are demanded. To stabilize the EOPL of the system, if it is possible, the environment temperature of gas cell can be controlled with a constant temperature. In practical applications, the real-time monitoring of EOPL with a direct measuring method may be necessary.

Paper Details

Date Published: 1 November 2016
PDF: 7 pages
Proc. SPIE 10157, Infrared Technology and Applications, and Robot Sensing and Advanced Control, 101572J (1 November 2016); doi: 10.1117/12.2246925
Show Author Affiliations
Hong Gao, Tianjin Univ. (China)
Xiuhan Cao, Tianjin Univ. (China)
Jinyi Li, Tianjin Polytechnic Univ. (China)
Zhenhui Du, Tianjin Univ. (China)

Published in SPIE Proceedings Vol. 10157:
Infrared Technology and Applications, and Robot Sensing and Advanced Control

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