Two versions of nonlinear Raman microscopy have lately captured the attention of several experimental groups. They are based on two important spectroscopic techniques, namely, coherent anti-Stokes Raman scattering and stimulated Raman scattering. Although experimental research progresses at a steady pace, conceptual investigations are hampered by heavy numerical calculations that are necessary to solve the vectorial problem of nonlinear interactions between electric fields and the matter being probed. Here, attempts at a simplified description of the vectorial structure of the nonlinear Raman response are examined in comparison with some examples conceived within the fully numerical treatment of the problem. The attempts are based on two different optical models. One is given by the three-dimensional Gaussian approximation which reduces the spatial complexity of the interaction between electromagnetic fields and matter to a volume with Gaussian profiles. This second strategy rests upon the breaking of the continuous character of diffraction in away that only diffraction angles that are optically relevant are used in the theoretical treatment of the fields. The two different methods are discussed and compared on the basis of some instructive examples. Fast calculation is ensured by the simplified models without loss of the spectroscopic information. © 2010 John Wiley & Sons, Ltd.
All Science Journal Classification (ASJC) codes
- Materials Science(all)