Open AccessExtinction measurement with open-path cavity ring-down technique of variable cavity length
Author(s) -
Hao Cui,
Bincheng Li,
Yu Han,
Jing Wang,
Chunming Gao,
Yafei Wang
Publication year - 2016
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.24.013343
Subject(s) - cavity ring down spectroscopy , optics , path length , extinction (optical mineralogy) , materials science , optical cavity , wavelength , cavity wall , length measurement , scattering , optical path length , absorption (acoustics) , molar absorptivity , physics , laser , composite material
Open-path cavity ring down (OPCRD) technique with variable cavity length was developed to measure optical extinction including scattering and absorption of air in laboratory environment at 635 nm wavelength. By moving the rear cavity mirror of the ring-down cavity to change cavity length, ring-down time with different cavity lengths was experimentally obtained and the dependence of total cavity loss on cavity length was determined. The extinction coefficient of air was determined by the slope of linear dependence of total cavity loss on cavity length. The extinction coefficients of air with different particle concentrations at 635 nm wavelength were measured to be from 10.46 to 84.19 Mm -1 (ppm/m) in a normal laboratory environment. This variable-cavity-length OPCRD technique can be used for absolute extinction measurement and real-time environmental monitoring without closed-path sample cells and background measurements.