Self-Referencing Raman Probes for Quantitative Analysis

Abstract

Diamond is evaluated as an internal reference for remote Raman spectroscopy using three different fiber-optic probe designs. The three probe designs include (1) a six-around-one fiber-optic probe with a flat diamond window; (2) a six-around-one fiber-optic probe with a quartz lens window with an embedded diamond particle, and (3) a filtered probe design with a flat diamond window. It is found that the second probe design provides a compact and inexpensive probe head which allows quantitative measurements of Raman-active analytes independent of changes in the incident laser power and independent of changes in the refractive index of the solution. In addition, the second probe design minimizes the glass Raman background from the fiber optics without the use of filters.