Raman spectroscopy is an analytical technique that can give us information about the structure of a molecule. Specifically it takes advantage of the vibrations of molecules. The vibrations of the molecules will result in a shift of the wavelength of the incident light and that information will be presented on the spectrum. See link below for an example.
Each type of vibration has a characteristic shift in wavelength so the bands seen in the resulting spectrum will identify (or at least narrow the options for) the particular type of bond that is present in the molecule to result in that shift.