Raman Spectroscopy over Optical Fibers with the Use of a Near-IR FT Spectrometer

A commercial Fourier transform infrared (FT-IR) spectrometer was modified for remote near-IR Raman spectroscopy. In one configuration, a single optical fiber was used to guide the excitation light to the specimen and to collect scattered light from the specimen. In an alternative configuration, separate fibers were used for excitation and collection. The optical fiber probes were used to record the Raman spectra of both liquid and solid specimens. The Raman scattering of the optical fibers interfered with the analyte signal. This fiber interference was affected by the optical properties of the specimen and the optical sampling configuration. These interferences were partially removed by subtracting a background spectrum. Potential applications and improvements are discussed.