ABSTRACT
In the early days of laser imaging, exploiting the Raman effect was relatively rare, mainly because of the low sensitivity of Raman scattering. With modern, highly sensitive spectral equipment, this has changed dramatically; in particular, the spectrochemical specificity—inherent to Raman spectroscopy and imaging—has instigated a wealth of applications in Raman microscopy (predominantly in the fields of biology and medicine). The chapter is structured along the lines of specific Raman technologies, as discussed in the earlier chapters on Raman spectroscopy, ranging from “ordinary” imaging based on linear Raman scattering; via enhancement approaches (e.g., in the form of SERS utilizing sensitized metal nanoparticles, or imaging at the nanoscale using TERS); to nonlinear Raman scattering (including SRS and CARS). For all of them, experimental and instrumentational peculiarities are outlined, and a wide range of examples are discussed, which highlight the current state of the art in Raman imaging. These include, for example, the recent efforts to drive Raman imaging toward superresolution, exploiting a combination of principles of stimulated Raman gain (SRG) and stimulated emission depletion (STED); or to incorporate novel laser sources into high-precision analytical Raman imaging, as encountered, e.g., in hyperspectral CARS imaging utilizing laser frequency combs.
