Recent content by diber

Did some further testing with the 2 units I have. Same power for mine... LD running at 400 mW and heater current optimized, I got close to 100 mW (see picture... highest point I have seen was 108 mW). However, you really have to look for the best maximum since there are several other local...

I just realised that I have probably come to a wrong conclusion in my post of 2 days ago about the need for an IR filter: I do not see any peak in the spectrum of the laser at 808 nm... however, higher up in the thread, there are 2 different WL mentioned for the pumping diode : 808 nm and 1060...

That is not exactly what I meant with the tuning of the heater. I did not actively control the heater voltage/current, and certainly not based on the temperature. I set it at the beginning (after a short powering up time) to achieve optimum beam intensity and then left it untouched. Under the...

Super nice build video and info in this thread ! I bought 2 of these from holokid some time ago to build into my raman spectrometer setup. They work super for that purpose ! The beams are fully polarized and can hence be combined with a PBS by mounting one laser horizontal and the other vertical...

So... took a while before I found the time to further investigate this... So far I did not manage to observe the spurious lines with the standalone laser and the spectrometer, probably due to the big intensity difference between the 532nm light and the 537 - 543nm light, which makes them...

Thanks Paul and kecked ! It seems that I will have to start probing the laser itself, especially considering the lines kecked is observing are exactly at the same position as the ones I am observing. And concerning the intensity ratio: I do observe the lines after the reduction by the long pass...

Thanks for the suggestions Paul. The peaks are gone when there is no light on the detector. I also thought about a spectrometer issue (especially because I have seen some hot pixels in them, indeed resulting in "fake" peaks) and made the measurements with 2 of them (both BW TEK spectrometers)...

Hello all, some reporting and some questions, especially to the laser specialists around here ! I have been playing around with the setup I described in post #74 above, improving alignment in order to increase the signal. It became quickly a (so far unsuccessful) chase for the origin of the...

Actually I meant to ask how small the laser spot on the sample is. Should be quite small and as such you could detect local changes in chemical composition on a very small scale by moving the sample!

In post #322 of the B&W Tech spectrometer thread, I posted a few raman spectra I managed to obtain with the 473nm laser and unmodified beam splitter (and if I am not mistaken, some other successful results were posted as well, but I could not find them back yet). Check also posts #468 and #478...

I can't keep up with your pace !! Impressive setup :bowdown:! Any idea of the size of the area you are effectively sampling with your setup through the microscope ? Should be quite small, no ? A challenge: you could motorize the x-y stage of your microscope and automatise the spectrum...

Hello chloderic, Your comments made me curious and I powered up the setup to do some test. Surprisingly, I did not manage to reproduce the high peaks around 548nm today. Since I took the previous spectra, I did remove and place back the dichroic mirror, hence its exact position and alignment...

That's how I started as well ! It is amazing that with a few tools, a bit (sometimes a lot) of time and effort, you can make new tools which make it much more easy to make yet more/better tools,... and before you know, you do not have enough space in the house/shed :crackup: Interesting...

A collection of nice posts in this thread !!! Interesting ! I have also cobbled together a raman setup with parts from the BW tec beam splitters, the optical fibers and a part from one of the 473 laser heads, in combination with some home-made parts (I am the lucky owner of a mill, lathe and...

As far as I understand these units, if you move the detector, it will be out of the focus of the focussing mirror. I think you would need a focussing mirror with a different focal length to make your idea work. The combination of multiple spectrometers should work (I am planning to do this as...