Raman-spectroscopy

[chloderic]

Based on various personal and public conversations, I would like to open a new special topic here.

This will be about all the relevant facets of RAMAN spectroscopy with individual DIY solutions, links to websites, sources of reference for hard and software or other topics here in the laserpointerforum.

Especially for me in the heart, because this nostalgic device deserves a rebirth ... :yh: , is the forum and solutions to use this device :

B & W-Tech Spectrometer & 473 module: Setup + Mods + Info

Link:

https://laserpointerforums.com/f42/b-w-tech-spectrometer-473-module-setup-mods-info-101467.html

 

[paul1598419]

Very nice first thread, buddy. As you know I am somewhat interested in this subject, but I'm sure you will know much more about it than I do now. Hopefully, that will change over time. I think what you have done to repurpose many items available on this laser to set up a RAMAN spectrometer is quite ingenious. I look forward to learning more about this subject from you. :yh:

 

[Civitus]

Based on various personal and public conversations, I would like to open a new special topic here.

This will be about all the relevant facets of RAMAN spectroscopy with individual DIY solutions, links to websites, sources of reference for hard and software or other topics here in the laserpointerforum.

Especially for me in the heart, because this nostalgic device deserves a rebirth ... :yh: , is the forum and solutions to use this device :

B & W-Tech Spectrometer & 473 module: Setup + Mods + Info

Link:

https://laserpointerforums.com/f42/b-w-tech-spectrometer-473-module-setup-mods-info-101467.html

Hi Chloderic !
Very good initiative.
Also, I am developping a Raman system with the B & W-Tech Spectrometer and 532nm laser.
I am very interrested in converting the eBay unit to a Raman system. May be we can work together on this?

These weeks I am quite busy, but from Jully I will be fully working on this project.
I have a quite good experience on Raman systems, i think that I can help. I got lot of stuff from thunderoptics.fr they sell lot of good quality parts for physics experiments, and i built my Raman system mostly based on their parts. If some one have a better source, please advise.

My question is mostly aboyt the 473nm laser linewidth and power. if the bandwidth is large, it will not be able to give a quite fine and strong signal as the power will be " divided" over all the pixels of the linewidth and it can be very low and almost of the intensity of the darknoise (remember that the ILX511 is very sensitive sensor and that the Raman effect signal is 1 over 10¨-6 of the excitation intensity, so one over a million of the laser intensity in the best cases !)

Thanks again, and i hope that we can creat good things here

C

 

[chloderic]

Hi Chloderic !
Very good initiative.
Also, I am developping a Raman system with the B & W-Tech Spectrometer and 532nm laser.
I am very interrested in converting the eBay unit to a Raman system. May be we can work together on this?

These weeks I am quite busy, but from Jully I will be fully working on this project.
I have a quite good experience on Raman systems, i think that I can help. I got lot of stuff from thunderoptics.fr they sell lot of good quality parts for physics experiments, and i built my Raman system mostly based on their parts. If some one have a better source, please advise.

My question is mostly aboyt the 473nm laser linewidth and power. if the bandwidth is large, it will not be able to give a quite fine and strong signal as the power will be " divided" over all the pixels of the linewidth and it can be very low and almost of the intensity of the darknoise (remember that the ILX511 is very sensitive sensor and that the Raman effect signal is 1 over 10¨-6 of the excitation intensity, so one over a million of the laser intensity in the best cases !)

Thanks again, and i hope that we can creat good things here

C

If you want to use the 473 nm laser from the assembly "B & W-tech Spectrometer & 473 modules: Setup + Mods + Info", you need a system with for example an optic from a transmitting microscope or something like the beam splitter described there. However, since I have used a reflecting microscope with completely different beam path in the illustrated composition (I also have a second other system) I need (because of the large working distance) a different laser power than the approximately 10mW from above described 473nm laser BWB-10-OEM 473. My DPSS laser with 532nm has only about 930mW, but I do not need this performance in my unfavorable constellation, because with 200-300 mW you can already reach measurable peaks in the stroke.
(see picture above ... the right peak is a ramanshift at 1330cm-1.

 

[Civitus]

If you want to use the 473 nm laser from the assembly "B & W-tech Spectrometer & 473 modules: Setup + Mods + Info", you need a system with for example an optic from a transmitting microscope or something like the beam splitter described there. However, since I have used a reflecting microscope with completely different beam path in the illustrated composition (I also have a second other system) I need (because of the large working distance) a different laser power than the approximately 10mW from above described 473nm laser BWB-10-OEM 473. My DPSS laser with 532nm has only about 930mW, but I do not need this performance in my unfavorable constellation, because with 200-300 mW you can already reach measurable peaks in the stroke.
(see picture above ... the right peak is a ramanshift at 1330cm-1.

yes yes ... I am planing to use two colimators from eBay and a beamspliter chamber and microscope infinity objective for my 532nm raman system.

But for the 473nm system, i would like to use the existing parts. it will be much cheaper.
C

 

[kecked]

The existing system Raman head has a filter you need to remove that blocks some spectrum and you already know about the internal spec baffles. I was hoping to move to 780nm for Raman The detector is pretty deaf down there and I might not even need a filter since it’s unlikely to even hit a pixel ...2400 or better I’m guessing so unless a different order wraps might work.

I have an Olympus scope I want to use. I think the optics will transmit 780nm. Can only try and see what I get. I’m looking for a toxin produced by toxic algae. The laser is to be a fiber telecom laser. Eventually I want to try a confocal and see if I can focus in on cell parts specifically for id.

So my point with a scope is you can select a very small area of an object to excite Raman and determine that portion and not the broad response. Is this correct. If not I’m in a dry hole.

 

[paul1598419]

I have several 532nm DPSS lasers that might work for this project. I have a 1300 mW lab laser, a 230 mW lab laser and modules that can be set anywhere from 100 mW up to 200 mW. I don't have a microscope as you have used in your setup and need to know what I would need if this is necessary. :thanks:

 

[Nordhavn]

Coherent Compass DPSS has the coherence length you need.

 

[paul1598419]

That is a very pricey way to go, though. It would be cheaper to control the temperature on a single mode laser diode and diffraction tune it to a very narrow linewidth. That could be done for maybe $300.00 in total.

 

[Agastar]

Based on various personal and public conversations, I would like to open a new special topic here.

This will be about all the relevant facets of RAMAN spectroscopy with individual DIY solutions, links to websites, sources of reference for hard and software or other topics here in the laserpointerforum.

Especially for me in the heart, because this nostalgic device deserves a rebirth ... :yh: , is the forum and solutions to use this device :

B & W-Tech Spectrometer & 473 module: Setup + Mods + Info

Link:

https://laserpointerforums.com/f42/b-w-tech-spectrometer-473-module-setup-mods-info-101467.html

Thank you, thank you, thank you! This is exactly what I got these for and I'm looking forward to following this thread.

I am a complete noob when it comes to Raman and I have spent a lot of time reading and watching videos. I have learned a lot but I still have a ton of questions.

I'm trying to build a raman system with the parts from the machine. I have removed the filter and baffles from the spectrometer and but I have not touched the optics in the beam splitter. I shined some light through the beam splitter box with the lid off and it looks like there is some coatings on there that change the color of the light a little bit. I was planning on running a full spectrum light through the beam splitter optics and then directly to the spectrometer to see what differences there were, however I have not done this yet (busy building my 3D printer kit). Now that the printer is up and running, I would like to get back to this.

My question, if I take a second unit and only remove the baffles, can I not perform raman with the supplied beam splitter?

Is there another reason besides fluorescence for using a 532nm laser instead of the 473nm laser?

I have some friends that are a part of a home school group and since I have several of these units, I would like to build a raman spectrometer and donate it to them. My thoughts were to remove the baffles and filter from the spectrometer and build it so that different lasers could be used.

Since I'm a noob still, I could use some guidance on this project.

Thanks again for starting this thread!

 

[chloderic]

I have several 532nm DPSS lasers that might work for this project. I have a 1300 mW lab laser, a 230 mW lab laser and modules that can be set anywhere from 100 mW up to 200 mW. I don't have a microscope as you have used in your setup and need to know what I would need if this is necessary. :thanks:

In the first step i would have a look around what i have. That means you MUST not buy in every case new parts. You may test the first assebly with parts you have on stock. The lasers you have may fit ALL, maybe with aditional parts. Which is the best laser you have, which one has the thightest and cleanest wavelength and can be regulated ? Depending on this .... do you have aditional parts you need like a beamsplittercube, beamsplitterdicro, colimators, optical parts from a telescope or microscope, some lenses?

I will say there are many many many ways you can go.

What you need is this list in any solution or combination:

- good laser
- beamspitting device (maybe DIY) , OR microscope OR semi-transparent mirror OR some other optics in this way
- beamleading like fiber or mirrors
- spectrometer
- analysing and postprocessing-software
- database of samples

OK, i will post bit by bit some DIY solutions.

Here the first .... possible modification of the knows beamsplitter to be used with a laser with other wavelenghts than the laser of the known unit, instead of the dicromirror a beamsplittercube, in such a case you need not compellingly a microscope, see pic attached.

Sorry that i am not as quick as i like to be to post, because it is a lot af work to disassembe parts to documentate them here ...

 

[paul1598419]

Yes, in addition to the parts available on these assemblies, I have PBS cubes, dichros, lenses of all sorts and diameters. If I don't have a telescope I can put one together with what I have here. Been reading up on Raman shifts in "Solid-State Laser Engineering", by Walter Koechner. Very informative stuff in there.

 

[chloderic]

Yes, in addition to the parts available on these assemblies, I have PBS cubes, dichros, lenses of all sorts and diameters. If I don't have a telescope I can put one together with what I have here. Been reading up on Raman shifts in "Solid-State Laser Engineering", by Walter Koechner. Very informative stuff in there.

You MUST not have parts of a telescope .... you may and are able to use such parts for an assembly as an alternate to other opto-mecanical parts. I wanted to say, that you could use such parts .... maybe a steak and beer will be an alternate too

 

[paul1598419]

I believe you misunderstood me. I use telescope and beam expander interchangeably, so all my lenses are made for lasers.

 

[chloderic]

I believe you misunderstood me. I use telescope and beam expander interchangeably, so all my lenses are made for lasers.

Hi Paul, yes ... sorry ... it seem so :beer:

 

[Agastar]

Yes, in addition to the parts available on these assemblies, I have PBS cubes, dichros, lenses of all sorts and diameters. If I don't have a telescope I can put one together with what I have here. Been reading up on Raman shifts in "Solid-State Laser Engineering", by Walter Koechner. Very informative stuff in there.

Whew, I'm WAY behind on my parts collection... :drool::bowdown: