What is the difference between dispersive Raman and FT-Raman?

Dispersive Raman, as its name suggests uses a diffraction grating spectrometer (essentially operating like a prism) to disperse the light scattered from a sample and then will detect this upon a multi-channel detector such as a CCD. The wavelengths of light detected are the Raman spectrum.

The FT-Raman system uses an interferrometer to introduce a path difference between the source and the signal beams to create an interferrence pattern - an interferogram, from which the Raman spectrum is re-constructed.

The Basic Dispersive Spectrometer