Erossel has a DIY raman project I think is very nicely put together. I’m very impressed. There’s another DIY Raman project out there but it doesn’t seem as active. The idea is to focus a laser on a sample and collect the light that comes out. It’s a lot like fluorescence, but the mechanism is different.

I am trying to choose the laser for a new system. The commercial Renishaw instrument in my lab has a 785 nm laser. That means the detector has to operate between 790 nm and 1100 nm. Most inexpensive detectors can’t do that very well. Cheaper off-the-shelf spectrometers can be used to detect the Raman signal from a 532 nm laser.

I suspect that fluorescence interference will be a problem for 532 nm Raman of beer. Certainly, 470 nm gives a significant (visible) beer fluorescence. From this paper, Fluorescence Spectroscopy for Characterization and Differentiation of Beers, it seems like 532 nm might not be too bad relative to 475 nm but I’d be willing to bet that 633 is considerably better. At this point I’m hoping that 633 is a good compromise. Plus, 633 nm lasers are cheap.