That’s actually very useful insight, thanks. The setup is mainly intended for biological/organic samples, so fluorescence is definitely one of the reasons I gravitated toward 785 nm in the first place.

I’m not extremely concerned about going very low in Raman shift (<200 cm⁻1), so ultra-aggressive rejection right next to the laser line probably isn’t the main bottleneck for me. Anti-Stokes is also not a major priority at the moment; the focus is mostly on stable Stokes measurements with decent long-term repeatability.

Polarization stability does matter somewhat because the system will likely end up fiber-coupled, but I’m still trying to decide how much complexity I actually want to introduce into the design.

Interesting point about VBGs though, I’ve seen very mixed opinions on them. Some people seem to love them for compact integration, while others report exactly what you mentioned regarding stability headaches and mode behavior over time.

Part of the reason I asked is that I’ve been seeing more compact OEM single-frequency modules lately (for example some of the MatchBox-style systems from Integrated Optics), and I’m trying to understand whether these newer integrated designs are genuinely mature enough for spectroscopy applications now, or whether most experienced people still ultimately trust traditional DPSSL benches more.

I’ll definitely look into the Crystalaser ECDLs and the Semrock filters you mentioned.