Abstract

A fiber optic approach for the determination of the carbon dioxide concentration in the gas or fluid phase during sequestration as well as for the sensing of the explosive TNT will be presented. The sensor consists of a quartz glass multimode fiber with core diameter of 200 µm and is based on the evanescent field principle. Cladding and jacket of the fiber are removed in the sensing portion, therefore interaction between light within the fiber and the surrounding medium is possible. A single-mode distributed feedback (DFB) laser diode with an emission wavelength around λ = 1.57 µm and a frequency doubled passively Q-switched Cr⁴⁺:Nd³⁺:YAG microchip laser (λ= 1064 nm) are used as light sources. The experimental setup and the sensitivity of the evanescent-field-sensor are characterized.

© 2008 Optical Society of America