Raman Spectrometry with High Sensitivity

Abstract

Raman spectroscopy, for well-understood fundamental reasons, is a relatively insensitive method of analysis, i.e., it is problematic to study dilute solutions, gases at low pressures, adsorbed species, etc. We describe instrumentation incorporating exit slit plane “multiplex” detection and demonstrate that the instrument improves in sensitivity over its conventional counterpart by a significant margin (in this case >X1000). The value that this increased optical efficiency provides is demonstrated and new applications of Raman spectroscopy are discussed. We include a discussion of the factors controlling the efficiency of illuminating and viewing opaque or highly scattering samples sensitive to high brightness lasers and demonstrate that most commercial spectrometers are set up in such a way that they perform in these cases much less adequately than need be.