Raman Spectroscopy: Stokes and Anti-Stokes Wavelengths

[sebitab]

Hi, For someone my question could be very simple but I couldn't find a well explain paper that explain this to me.

In a Raman spectrometer the stokes and anti-stokes wavelength will always be grater than the laser wavelength used?.

I have this confusion because I saw that Raman spectrometers commonly use an edge filter that is usually a couple o nm grater than the laser wavelength.

For example for a 532nm use a 534 or 538nm edge filter to reflect only the stokes and anti-stokes wavelength.

If some one can explain this to me I will appreciate it.

 

[alxm]

By definition the Stokes lines have a longer wavelength and the anti-Stokes lines a shorter wavelength.
So if you have an edge filter with a wavelength longer than your excitation source, you should only be seeing the Stokes lines. Which lines you want to look at depends on the kind of Raman spectroscopy you're doing.

 

[sebitab]

Thank you very mauch alxm.