Article Cite This: Anal. Chem. XXXX, XXX, XXX-XXX
pubs.acs.org/ac
Analysis of Fiber-Enhanced Raman Gas Sensing Based on Raman Chemical Imaging Di Yan,† Jürgen Popp,†,‡,§ and Torsten Frosch*,†,‡,§ †
Leibniz Institute of Photonic Technology, 07745 Jena, Germany Friedrich Schiller University, Institute of Physical Chemistry, 07743 Jena, Germany § Friedrich Schiller University, Abbe Center of Photonics, 07745 Jena, Germany ‡
S Supporting Information *
ABSTRACT: Fiber enhanced Raman spectroscopy (FERS) is an arising new technique for versatile highly sensitive and selective multigas analysis in various applications, such as environmental monitoring and medical breath diagnosis. In this study, the performance of FERS was thoroughly studied with the help of a specially designed multichannel Raman chemical imaging. Several types of hollow core photonic crystal fibers were thoroughly analyzed in terms of their performance in light confinement and sensitive gas sensing. The optimal fiber length for Raman gas sensing was found to be 15 cm in our spectroscopic system. To separate the Raman scattering of the target gas molecules from the background generated by the silica microstructure of the fiber, the optimal diameter of a spatial filter was analyzed and quantified as Ø3.9 μm, which balances the suppression of the silica background and the attenuation of the gas signal, originating from different regions in the plane of the fiber end-face. To achieve an easy-to-use gas monitoring system with stable performance, an automated coupling-method was developed, to simplify the alignment of the FERS setup. The optimized design of the FERS setup has remarkable potential for highly sensitive, miniaturized, easy-to-use, and versatile gas sensing. characteristic Raman bands of oxygen (1555 cm−1) and other interesting gas analytes in the fingerprint wavenumber region (
