Raman versus CARS microscopy: When one is better than the other

Since the first introduction of Raman microscope in 1973, optical and laser technology has made a tremendous step forward. However, despite of the obvious advantages of being very informative and nondestructive method of studying biological samples, spontaneous Raman scattering suffers from a series of limitations, such as a fluorescent background and a low signal level. Nonlinear Raman spectroscopy, and, in particular, spectroscopy of coherent anti-Stokes Raman scattering (CARS) can resolve most of the problems associated with conventional Raman spectroscopy. In this report, the most critical issues of the CARS microspectroscopy setup design are reviewed, and several exciting potential applications of the broadband CARS microspectroscopy, where the CARS microscopy has an advantage with respect to Raman microscopy, are outlined.