RGB Diffraction Grating

OK, I will have to study this for awhile, found some good info here, for those interested in the same:

http://www.fresnel.fr/files/gratings/Chapter1.pdf

Alaskan said:

LazeristasUVISIR
Do you know of any high efficiency gratings which can do more than 80%?

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I think efficiency can be affected by the polarization of the light. S polarized is more efficient I think. There's a good chance I'm wrong, so I'd recommend doing your own research .

That isn't a tube of light; it's just a poor choice of colors to represent the beam profile intensity.

Also you can use a prism to perform the beam combining based on the refraction. Just look at H2Oxide's pic. You can also use specially designed trichroic prisms found in 3CCD cameras.

Better than one of these cubes? It must be or you wouldn't suggest it, what makes it better? Eager to know more. All I can find on ebay are the cubes: Trichroic Cube Prism RGB Combiner or Splitter 23mm x 23mm x 22mm | eBay

Googling, I found this:

Abstract


A trichroic prism assembly design, believed to be new, is proposed and demonstrated. This new design has the advantages of low s- and p-polarization dependence in the reflectance spectra of the optical coatings. Hence it can be used for both color separation and color recombination with polarization change. This new trichroic prism assembly is especially useful in a compact color projector employing reflective liquid-crystal light valves.

© 2000 Optical Society of America

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I'm finding lots of 3CCD cameras on ebay which can be had fairly cheaply, maybe time to get one that way if they will do what I need: http://www.ebay.com/sch/i.html?_odk...X+3ccd+camera.TRS0&_nkw=+3ccd+camera&_sacat=0

Reading this thread: http://208.71.46.190/search/srpcach...=us&sig=Rf_ofbqU31sWwU3uW5Jx.Q--&fr=yfp-t-574 - My take is that a X-prism might be better?

I've been trying to think outside of the box on how to make a laser out of my 12 sets of R,G,B laser diodes and so far, I'm not getting out of the box very far. Keep coming back to the idea of trying to get all of the diodes as close as I can together without lenses, shoot all the raw light at one lens and collimate it together after they have expanded quite a bit together. Or, just to mount them all individually with their own individual lenses and let divergence turn it white at the end of the beam path.

Of course there is the knife edge path to what I want as the final output, but I don't like it very much due to the expense of all of the mirror mounts needed but I might be stuck with it.

I found a couple of diffraction gratings on ebay out of a fluorometer which used to output 200-700nm when paired with an arc lamp which might be interesting to use, but the loss is high compared to glass optics.



Ultimately, I want to control the color output of the laser, mix as needed to make lots of colors, a combined output for a white beam would be cool too.

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If you still want to go down the trichroic prism route, I found this: Broken 3CCD Camera. Unlikely anyone else will bid as it's listed as "for parts or not working". Unless of course someone else is looking for a Philips trichroic prism too . As far as I can tell by the very short description, the prism is intact. (If you don't go for it I might )

Id buy it for a reasonable price but they won't ship to Alaska.

X-prisms work okay too. They usually need the light to be polarized, but your laser light usually is anyway.

H2Oxide said:

If you still want to go down the trichroic prism route

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I bought a prism from Surplus Shed that fits this discription. Red, blue, green out 3 sides when white light enters 4th side. I can take pictures of it if anyone needs them. I hope I'm not confused and now confusing you guys.

Link to item LARGE MTD CUBE BEAMSPLITTER/COMBINER-1 IN-3 OUT OR 3 IN-1OUT - Surplus Shed

starlight said:

I bought a prism from Surplus Shed that fits this discription. Red, blue, green out 3 sides when white light enters 4th side. I can take pictures of it if anyone needs them. I hope I'm not confused and now confusing you guys.

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You can find the cubes all over Ebay, is it a cube or does it look something like this: Philips trichroic prism? It's hard to tell from the photo on their site. Not sure what the advantages/disadvantages to this style over the cube are, perhaps someone with a little more knowledge can tell us.

I've heard the cubes are lossy compared to using mirrors to combine colors, so I decided to go with mirrors until I saw how spendy the mounts would be for 36 of them. I found some 2 x 2.5 x 2.5 inch diameter cubes on ebay, although that's pretty big, does anyone know of any others which are even larger to be found for sale anywhere? I want to play with combining the raw output of several laser diodes into the cube. I also found two listings of 3CCD trichroic prism's on ebay with CCD's and prisms all together in an assembly for sale.

Edit: Here's one, they look very small, anyone know if this is standard, to be so small?

http://www.ebay.com/itm/361022439780

Alaskan said:

so I decided to go with mirrors until I saw how spendy the mounts would be for 36 of them.

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You can build your own mounts, it would take some time, but it would be a lot cheaper than buying them.
Some old schematics I had gave detailed instructions on how to build them.

H2Oxide said:

You can find the cubes all over Ebay, is it a cube

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Yeah it's a cube.

Alaskan said:

I've heard the cubes are lossy compared to using mirrors to combine colors, so I decided to go with mirrors until I saw how spendy the mounts would be for 36 of them. I found some 2 x 2.5 x 2.5 inch diameter cubes on ebay, although that's pretty big, does anyone know of any others which are even larger to be found for sale anywhere? I want to play with combining the raw output of several laser diodes into the cube. I also found two listings of 3CCD trichroic prism's on ebay with CCD's and prisms all together in an assembly for sale.

Edit: Here's one, they look very small, anyone know if this is standard, to be so small?

http://www.ebay.com/itm/361022439780

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What is on the other side?

I have this weird mirror on a chip from a DLP TV I can't figure out.

Starlight, which camera did that come out of, do you know? I have no idea what that mirror is for either.

Alaskan said:

Starlight, which camera did that come out of, do you know? I have no idea what that mirror is for either.

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it was from a Samsung 61in DLP TV. I wanna know if it moved in some way. Why does it have power to it.

You're going to need some adjustable mounts whether you use the prism or dichros. Usually it's easier to adjust using dichros fixed to mounts than try and adjust the laser heatsink/holder so that it correctly aligns with the prism.

Here are the two types of relatively inexpensive adjustable mirror mounts I have found, which do you prefer yourself Bionic-Badger and why? I've heard one of the two types doesn't require readjustment, the other will, can you confirm that for me? Maybe you or someone has something better to recommend?



A: Once set, you can leave it?

B: Requires periodic re-tweaks?

This is a test, answering will provide a plus rep (When I asked each seller which was better, theirs or the other, they both said theirs, of course).