Cone mirror

[The_Doctor]

The only way it's going to happen is to try to bridge between the ideal, and as close as we have already. Which is Meredith Instruments corner cube reflectors, 22mm type, found on eBay last time I looked for any (or sourced from the Chinese firm that makes them, and they shouldn't have to be that big anyway, 1cm might be ideal)... But those aren't mirrored on the outside surfaces, so that would have to be done. I can't afford to, and no-one else seems to want to.

There was talk of a four-sided axicon but that's even worse, because it would have to be made from scratch, unlike the corner cube, and anyone can easily demonstrate that the beams from such an axicon cannot tesselate compactly into a fine beam as closely as a three-sided one anyway. People have argued that aligning it would be easier, but it's not true, as machining and aligning parts for a three-sided system with its odd angles is actually easy, I worked out a design where the mounts can easily be cut with 20° angles on a crude bandsaw and take two drilled holes, one threaded, and still be finely and easily adjusted with two movements per diode mount, and one fore/aft translation and rotation of the axicon itself.

Knife edging can set beams close together, but the more you do it, the more interesting (and unlikely) the mirror shapes become, if you're really going to fit more than about 3 beams together. I worked out that 3 very close-set beams can be done by using spare Medialas Widemove scan mirrors, I think I included an image of that layout somewhere in that thread or elsewhere here. To do it with mirrors you need several more points of rotation or translation combined than you do with the 3-sided axicon (means complex mounts!), but unless someone makes an axicon with 6 sides, or bores the axis of a 3-sided one for a 4th beam, there's no point in planning for them because no-one can surmount the cost and effort to do it.

Edit:
If the mirror were a simple curved-surface cone it could not work, as the beam divergence would be like a flame thrower. Actually more like a floodlight.

[edison]

I would love to try a meredith corner cube reflector to get it coated. If i know where to do that i can try to find also a piramid and see if we can do both.

If you have info where i can get a high reflective coating on a corner cube reflector let me know.

If its possible i,m willing to putt some money in it

If you have a good design i will even ask a manufacturer in the neighborhood to make the mechanics for this. Shoot me a PM so that i can work with you on this together if you want.

[The_Doctor]

Hell no.
Not personal, I just don't want to get into that project again right now. If you look for my posts in that thread towards the end you can see the confusion and conflicts of ideas and wishes that explain this, but more importantly you can see any info I ever had, I put it all out there, except the details of my diode-mounting-and-aligning scheme, which I laid in plenty of clues about anyway. If you decide to go ahead with a corner cube being mirrored, let me know, I'll let you have private access to the design as a reward for committing to the scheme. You can probably improve on it too, but it's workable as is. The details I can give you are a Sketch-Up 3D design file, and some images dumped from it, plus some text notes on simplifying construction methods. I didn't publish this last detail (though I think I gave a copy to Jem once), because I saw people rejecting my scheme in favour of one I beleived to be a lesser design. Can't force horses to drink so I kept the water to myself. You're the first person in over 2 years who seems interested, so I'm interested in how far you'll go. If you get a corner cube coated and will try my design, I'll give you every detail I have.

[edison]

That,s fair and very hounestI will try to get a cornered cube first then. Thanks for the info

[The_Doctor]

You're welcome. Haven't given you much yet though...
Try this:
http://cgi.ebay.co.uk/25mm-CORNER-CU...item2ea9b30fdd
(Could be better to search for listing 200415580125 from your local eBay site though).

That thing appears to be silver enough on the back too, and maybe has some kind of protective layer over it. If your question to Meredith Instruments (seller) is short and direct you'll likely get a fast answer. Obviously the (originally) front round surface won't matter and will be fitted to some kind of mount that moves on axis and can rotate, and be clamped in place once set. If you find that it does have a good mirrored surface on it for reflections off the back, then you're sorted, and I ought to buy one too. Ask them though, it might even be an UNcoated retroreflector, as the originating company sells those too. MI's listing does NOT distinguish between types, nor is it easy to tell from those images.

In any case, this one's still a bit big, but it's a start.

[edison]

Within a few weeks the driver with the collimators and diodes are ready. I can buy one of these and get it coated. I will ask meredith. I dont have a setup right away but i like the idea. Its not a case of if but when

[mixedgas]

I had the axicons made, solid glass, I need to find a coating house.

steve

[The_Doctor]

Well, if you can find one and will get one of those MI retroreflectors in there for me, I will be all sweetness and light. I'm still not even sure if they need it, though I think I asked them once and they said they were uncoated. Either that, or I found the maker sold them cheaper that way. If they ARE coated already and also properly shiny on the outside, then it's probably not easily beaten without a dielectric coating, and that might really be hard to blag.

[logsquared]

I have a four sided axicon with a hole in the middle. check out post #178 in the axicon thread. http://www.photonlexicon.com/forums/...e-beam./page12

[mixedgas]

If I get some time next week I just may laser scribe some thin mirror, we can hit +/-.002 with the one pulsed co2.. Note I said scribe. Not cut....

Steve