The Pulsar Engineering Community Board

There are two variables that can be used to define the noise of a spectrograph which are often mixed up. Here is a bit of clarity in that mix: Signal to Noise Ratio (SNR) which is technically how much noise is contained in every pixel of your data. To obtain it you typically take at least 10 spectra...

The issue with single mode fiber is that it's very difficult to couple the signal into it. And the big disadvantage of the larger core fiber is that you loose a lot of light. I remember that my boss tried to make an OpenRAMAN reproduction at the office except he decided to change the design to use a...

Considering the noise level in the spectrum shown, I would say that the approximation of ~5°C is not that far from reality.

I really have to take a moment to read that paper to get a better understanding of the experiment!

Is the setup at the VUB main campus in Etterbeek?

If so, maybe we can arrange a visit so that I have a look at your setup directly. Contact me via private message if you're interested.

My recommendation is to take the blank exactly like how you'd do the measurement but just switch the laser off - then switch the laser back on, wait for stabilization if required, and perform all your measurements. So I do it with the test tube in place :) And I even try to stay at the same position...

It's not going to be as-sensitive as an interferometer (which will react to people slamming doors etc.) but you might want to isolate it a bit in harsh environments. You have plenty of choices for that, but I'll focus on sorbothane feets: https://www.thorlabs.de/newgrouppage9.cfm?objectgroup_id=6421...

Something that I can add also is to take into account the fluorescence of the supporting medium. At the maximum exposure time of the camera, 32 seconds, I reach the fluorescence of water at ~50 mW so it makes no sense to use more power unless I plan to take shorter exposure time. That's if you want ...

That's pretty much it. As mentioned, the weak point is (used to be) the camera bracket but I already redesigned it -- just not released yet. With gentle driving and the spectrometer in a box with bubblewrap it shouldn't be an issue. For "production" grade stuff I would make a few changes: ...

I confirm that typical price for a Raman probe is usually above 2k$. Big part of the reason are already the higher quality filters they use (steeper rejection) which, alone, already cost $1600. Optics can become quickly very expensive! https://www.chroma.com/products/sets/49952-rt-raman-532nm-laser-...

That's to be expected. Raman is pretty weak so we use very high exposure time and gain. But if you check regular scattering (not even to mention reflection) the order of magnitude is typically ~1:10^9 so an OD of ~9 or close to 9. Typical filters have rejection of OD 6 to 7 so even with the edge fil...