Hey All

[BDi]

Hi

I am a noob who has been doing some research and reading of the forums prior to joining.

In doing so, I started designing my very first concept.

From my limited understanding, I have hand sketched up my greenhorn design and in brief my concept uses multiple lasers combined using cubes.

I understand the beam joining & splitting limitations of cubes and using knife edging, but from my research my concept of combined seems plausible, but to know for sure there's a whole raft of expert opinions, views and advice I need.

So, in a nutshell, I'd like to chat with a veteran who can tell me if I am crazy or not prior to making myself look like a total loon in the forums...

Are there any volunteers?

Cheers

BDi

p.s. Thanks for all the info everyone has contributed so far.

 

[Dutch67]

Welcome. I'm sure someone here can help you out.

 

[BobMc]

Welcome to the forum. It might be better to go ahead and ask your questions that way those people that can help will know what is is you need to know. (Trying to be helpful.
) Once again welcome and be safe and enjoy and safety glasses .

 

[BDi]

Well, here goes...

Using my chicken scrawl attachment as a reference, I was wanting to know if this was a viable squence for combining laser beams:

1. Ref A - Combine 2 lasers of the same colour using a polarizing cube into Beam A.

2. Ref B - Combine 2 lasers of the same colour using a polarizing cube into Beam B.

Combine beam A and B into a single beam using a dichroic filter to become Beam AB.

3. Ref C - Combine 2 lasers of the same colour using a polarizing cube into Beam C.

Combine beam AB and C into a single beam using a dichroic filter to become Beam ABC.

4. Ref D - Combine 2 lasers of the same colour using a polarizing cube into Beam D.

Combine beam ABC and D into a single beam using a dichroic filter to become Beam ABCD.

5. Ref E - Combine 2 lasers of the same colour using a polarizing cube into Beam E.

Combine beam ABCD and E into a single beam using a dichroic filter to become Beam ABCDE.

Deliver Beam ABCDE through a beam expander.

 

[CurtisOliver]

Welcome to the forum BDi.
There are many on here that can help.
Encap and Diachi come into mind on this one, I also don't mind checking out your drawing to see if you are on the right track with your thinking.
Enjoy your stay! :beer:

Edit: You added as I was posting.

 

[BobMc]

Don't know if these will help but I bought these off a member and did a review on them ~~ http://laserpointerforums.com/f52/10-12-watt-450nm-review-99144.html~~~~ http://laserpointerforums.com/f52/2-8-watts-520-a-99146.html hope it helps . :thinking:

 

[BDi]

Don't know if these will help but I bought these off a member and did a review on them ~~ http://laserpointerforums.com/f52/10-12-watt-450nm-review-99144.html~~~~ http://laserpointerforums.com/f52/2-8-watts-520-a-99146.html hope it helps . :thinking:

Was that meant for me? Also, could you please recommend a topic/ area I should post my concept?

 

[BDi]

Welcome to the forum BDi.
There are many on here that can help.
Encap and Diachi come into mind on this one, I also don't mind checking out your drawing to see if you are on the right track with your thinking.
Enjoy your stay! :beer:

Edit: You added as I was posting.

LOL! I noticed!

Did you have any feedback?

 

[CurtisOliver]

What wavelengths do you have in mind for A-E?

 

[BobMc]

Was that meant for me? Also, could you please recommend a topic/ area I should post my concept?

Yes, thought you might want to see how someone else pbs'd two beams together? I didn't build them so I can't give much tech help. Just thought you might want to see. You can post in "general" or in the wavelength thread that you like to build in, as has been mentioned. Either, I'm sure would be good. Best wishes with your build, looking forward checking out what you build.

 

[diachi]

Well, here goes...

Using my chicken scrawl attachment as a reference, I was wanting to know if this was a viable squence for combining laser beams:

1. Ref A - Combine 2 lasers of the same colour using a polarizing cube into Beam A.

2. Ref B - Combine 2 lasers of the same colour using a polarizing cube into Beam B.

Combine beam A and B into a single beam using a dichroic filter to become Beam AB.

3. Ref C - Combine 2 lasers of the same colour using a polarizing cube into Beam C.

Combine beam AB and C into a single beam using a dichroic filter to become Beam ABC.

4. Ref D - Combine 2 lasers of the same colour using a polarizing cube into Beam D.

Combine beam ABC and D into a single beam using a dichroic filter to become Beam ABCD.

5. Ref E - Combine 2 lasers of the same colour using a polarizing cube into Beam E.

Combine beam ABCD and E into a single beam using a dichroic filter to become Beam ABCDE.

Deliver Beam ABCDE through a beam expander.

That'll work, as long as the wavelengths of A, B, C, D and E are far enough apart for a dichro to work. There are some really narrow dichros out there but they aren't cheap and often need some "angle tuning" to get good performance - meaning they don't work well at the regular 45 degrees angle of incidence. What wavelengths are you thinking of going with?

Nice thing about dichros and PBS cubes of course is that you can stack the beams directly on top of each other, unlike with knife edging where they are next to each other (sort of how it looks in your diagram, I imagine that's purely for demonstration purposes).

Your beam expander would need to be achromatic (unless you don't care about mild chromatic aberrations), keep that in mind. Typical lenses have slightly different refractive indices at different wavelengths (larger for shorter wavelengths) so with a regular expander your different wavelengths would be focused slightly differently, resulting in chromatic aberrations.

Achromatic lenses/systems have an equal refractive index at multiple wavelengths.

 

[CurtisOliver]

Yes, the wavelengths of which you are hoping to use is very important to whether or not your idea is feasible.
Good suggestion on the achromatic lens Diachi.

 

[NightExplorer96]

Hello

-Alex

 

[paul1598419]

Was going to chime in here, but diachi beat me to it, again. Welcome, and good luck with the largest number of PBS cubes used by a member in a single build project I've seen so far. In the end, chromatic aberrations will be your greatest problem. An achromatic lens system for a BE is never cheap.

 

[Encap]

Well, here goes...

Using my chicken scrawl attachment as a reference, I was wanting to know if this was a viable squence for combining laser beams

What Diachi said +

Do you envision doing this on an optical bench? What are you trying to achieve--might be a simpler way?

Sounds like an expensive thing to do requiring very careful precise alignment of many elements and a very stable, rigid, as vibration free as possible, platform to hold all the elements in exact place depending on the quality of the results you are looking for.

Dichoric filters will work if ABCDE are all different wavelengths/no two are the same wavelength.
"Dichroic Filters--Common use:
Combining lasers of the different wavelengths once.
Dichroic filters reflect a beam of one wavelength and transmit a beam of another wavelength. You can only do this once with each wavelength.
Example:You can not combine 532nm and 660nm together, then combine that beam with 660nm again.
Example:You can combine 660nm, 638nm, 589nm, 532nm, 445nm and 405nm together using dichroic filters.
Advantages:Can combine multiple beams with different wavelengths.
Disadvantages:Cannot be used to combine the same wavelength."
From LPF REF. thread, see: http://laserpointerforums.com/f51/reference-guide-how-combine-lasers-77449.html

For a more complicated discussion of combining is a 2005 paper on combining from MIT "Laser Beam Combining for High-Power,High-Radiance Sources"
see: https://www.ll.mit.edu/news/Fan_LaserBeamCombining.pdf

 

[paul1598419]

Another way of saying this is that the first dichro needs to pass A and reflect B, the second dichro needs to passs A+B and reflect C, the third dichro must pass A+B+C and reflect D, and that last poor dichro must pass all of A+B+C+D and reflect E. See how complicated it gets the more dichros you put into the system?