Abstract

We have developed a unique all-silica fiberoptic probe that has the advantages of being simple and inexpensive to fabricate. The probe is useful for Raman, fluorescence, absorption, reflectance analysis over a wide temperature/pressure range and in corrosive chemical environments. The all-silica probe comprises one light exciting and six signal collecting optical fibers that are fused into a quartz tube under reduced pressure. No epoxy materials are required in the fabrication of the probe. Thus constructed, the probe is essentially a SiO₂rod that maintains the optic characteristics of the individual fibers and has the thermal and chemical properties of SiO₂. We have evaluated the use of all-silica fiberoptic probe for normal Raman spectroscopy and investigated silver doped sol-gel films directly coated on the probe head for surface enhanced Raman scattering (SERS). The silver doped sol-gel films exhibit strong enhancement of Raman scattering from molecules adsorbed on the metal surface. We have applied the SERS-active films to both organic and inorganic analysis. In contrast to other silver surfaces, SERS response on our films develops rapidly and remains stable over long period of time (48 hours or more). We have also demonstrated analytical SERS enhancement for many inorganic ions, e.g. ${\text{UO}}_2^{2+},{\text{CO}}_3^{2-},{\text{NO}}_{3^{-}},{\text{NO}}_{2^{-}},{\text{SO}}_4^{2-},{\text{SO}}_3^{2-}$. This presentation will describe and discuss our recent efforts toward the development of the all-silica fiberoptic probe, the fabrication of silver doped sol-gel films, and the analytical usefulness of both concepts.

© 1996 Optical Society of America