Using a PMT/Monochromator, we have Surface Enchanced Raman Vials we are using to analyze samples. One thing I am trying to figure out: The so called finger print region is 500-3000 wavenumbers after the wavelength of the laser you are using. In our case, we are currently using a 200mW 532nm laser. So, I've set the monochromator to scan from 545-632 (approximate numbers). The problem is I am seeing around 18,000 photons at 545-547 and then it drops off to around 1,000-3,000. I think the 1,000-3,000 photons are a result of the Raman scattering, but why is the 545-547 range so high? Do you think a 532nm subtraction filter would help this problem? Also, this is a very basic question but we are also using a photon counter to measure interrogate the signal from the PMT. What is the methodology behind determining what the Photon counter should call a photon i.e. how do I determine the amount of volts the Photon counter calls a photon? Maybe use something like E=hv? Thanks for your time!