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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...

Your print turned out very nice (cleaner print then mine :shhh:). Thanks, glad I could help ! Your picture confirmed a small issue I noticed with the box-design for my spectrometers as well: the openings for the fiber input and for the power connector are not perfectly centered. Did it...

The potential problem is that we are not doing linear regression (best fit of a linear function to a number of points) but higher order regression (due to the optics/CCD configuration, a linear function is not very accurate to describe the relation between pixel number and lambda... both Ocean...

Re: B&Wtech 473nm unit / Spectrometer Mods & Info I tend to agree with Agastar on this. I have been involved in the development of space-borne imagers (not hands-on, but close enough to have seen quite a number of details here and there) and for such imagers, these dark pixels are used in the...

Re: B&Wtech 473nm unit / Spectrometer Mods & Info Found another source of plenty of lines throughout the spectral range for these spectrometers: spark emission of metals. With the collimating lens of one of the beam splitters, the optical fiber and a re-wound microwave oven transformer...

Re: B&Wtech 473nm unit / Spectrometer Mods & Info The phosphor coating causes indeed very broad peaks in the spectrum and can change from brand to brand and lamp type to lamp type. However, the discrete lines from the individual elements are still clearly present above this wide background...