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RGB beam combining with prism?

Gryphon

Gryphon

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Wow thats neat, it does seem impractical from a space stand point as you said. Interesting that even though you did use two wavelengths that were VERY far apart, then ended up needing to be very close to one another in terms of angle, i don't know how you would get a green inbetween them
 





H

Helmholtz Watson

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That's pretty cool! At least now I know it'll work but probs going to have to wait a few days 'till i finish moving house. My laser modules are considerably slimmer than those so should be able to fit the green in fairly easily.

Are the laser dots on the wall from internal reflection in the prism? If there's such a thing as a silvered triangular prism (the side facing the camera) it would work even better.
 
M

maxh

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You could always use mirrors to fold the path up and get more effective distance from the prism and therefore more separation between the input beams, but with each bounce you'll lose some light.
 
Cyparagon

Cyparagon

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That's right, max. However, the green will need to be closer to the red than the bluray. ≈⅓" I calculate at 3 ft. that's about 8mm so there will be <5mm between the beams themselves even at 3 ft. If you allow for the mirror edges and mirror mounting hardware, that's about all the closer you can get anyway.
 
D

Deleted member 8382

Guest
Very interesting idea here. Where can I find a small prism for cheap to experiment with?

Yours,
Albert
 
H

Helmholtz Watson

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I'd thought about using 2 longish mirrors parallel to each other with the lasers reflecting multiple times to get a long beam path in a short space but it would lead to fairly high losses as I don't have great mirrors available.

Ebay has a fair few prisms available for decent prices.
 
T

Things

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You could just use the good ol RGB dichro setup, they are much more practical and efficient than a prism. Another possibility may be those RGB combiner cubes from data projectors.

Interesting experiment, though :)
 
H

Helmholtz Watson

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Things said:
You could just use the good ol RGB dichro setup, they are much more practical and efficient than a prism. Another possibility may be those RGB combiner cubes from data projectors.

Interesting experiment, though :)
Click to expand...

Thats just it, it's an interesting experiment. That is my only motivation for most of the things I do. Everyone uses dichros, therefore it's less interesting.
I would quite like an RGB combiner cubes though (Are they those 3 or 4 piece compound prisms?)
 
Cyparagon

Cyparagon

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Here is a basic small equilateral prism for $1 plus shipping. And here is the search for some other sizes and shapes for under $10.

That's where I got mine, anyway.
 
M

maxh

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X-laser said:
should work BUT you never would get clear white unless you replace violet by blue one!!

of course, don't forget to adjust the power of each laser to match the same visibility of them!
Click to expand...

You can use violet instead of blue just fine. You can achieve a perfect white balance, you just have to adjust the amount of each color. See The perfect white balance over at PL for some good info on color mixing.
 
Cyparagon

Cyparagon

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X-laser said:
should work BUT you never would get clear white unless you replace violet by blue one!
Click to expand...

Ya know, it really bothers me when people talk out of their ass. Have you tried it? Have you any proof that it doesn't work? or is it pure speculation? If it IS pure speculation, you had better SAY that in your post! :mad:

Helmholtz Watson said:
Hmm. Christian scientific apparatus? Does it work or do you just have to believe it does?
Click to expand...

Rawful! I know, most unlikely source. It isn't laser grade per se... just basic uncoated glass components, but they really work just fine. They have large cheap lenses of varying focal lengths as well. Remember X-files?

flying-spaghetti-monster.png
 
D

Deleted member 8382

Guest
Cyparagon said:
Here is a basic small equilateral prism for $1 plus shipping. And here is the search for some other sizes and shapes for under $10.

That's where I got mine, anyway.
Click to expand...
Do you think the 1$ unit will do the trick? it says it's really small, but others are lust larger by side, and for what we want them... XD
 
Cyparagon

Cyparagon

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Yeah, the dollar one is plenty big enough for a laser beam. It's just probably insufficient for those typical sunlight demonstrations.
 
D

Deleted member 8382

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good. How much does it cost and how long did it take for them to ship it to you? Are you in USA?
 
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