Fiber Raman background study and its application in setting up optical fiber Raman probes

Fiber Raman background spectra of different types of fused-silica fibers are studied and compared. The results show the following: (a) all the background spectra are very similar and comparable with Raman spectra of fused silica, regardless of the difference in the cladding and buffer materials; (b) the overall background intensity increases with the fiber numerical aperture but has no obvious relation with the core diameter. Both experimental evidence and theoretical explanation have been provided for these views. A simple and unfiltered fiber probe for surface-enhanced Raman scattering detection with low fiber Raman background interference is constructed, and the optimum configuration of the probe is suggested and discussed based on the results of the background study. (C) 1996 Optical Society of America