Self-referencing Raman probes for quantitative analysis

Diamond is evaluated as an internal reference for remote Raman spectroscopy using three different fiber-optic probe designs, The three probe designs i nclude (1) a six-around-one fiber-optic probe with a flat diamond window; ( 2) a sh-around-one tiber-optic probe with a quartz lens window with an embe dded 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 ine xpensive 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 secon d probe design minimizes the glass Raman background from the fiber optics w ithout the use of filters.