I currently have a 540nm long pass filter. Since I don't have a notch filter I would need to buy a new filter (eg short pass) to look at anti Stokes.

If I understand your suggestion, we can try a lower energy laser to avoid fluorescence excitation, right? So I see a few options:

1) Get a higher wavelent laser and a new long pass edge filter. Pros: at higher wavelenth fluorescence will be less of an issue. Cons: less ramman emmision and lower CCD efficiency (can be overcome with a more powerful laser). I have a cheap red laser I can try to check for fuorescence (I don't think I need optical filters for that). Can cross check the test with an equivalent 5mW cheap green laser to see if longer wavelength turns fluorescence off.

2) Get a short pass edge filter and look for anti-stokes radiation. Pros is that fluorescence should be gone (the trend for fluorescence can be seen in the plot and it does indeed dissapear near the excitation energy). Con is finding a reasonably priced filter (shortpass don't seem to be as overstocked). And another Con is a lot smaller Raman signal on the anti Stokes side.

3) Analyze the fluorescence out with math (fluorescence is smooth, Raman is spikey). Data is posted so any nexian interested can give it a shot.

Soo, you are suggesting going down 1), right?

I'll give the "poor man's" fluorescence test a shot and report back. Wife made me take the setup down so it may be a few days.

Many thanks for the explanation and suggestion.