un0me2
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Cutting Calcite (Iceland Spar) Crystals for Beamsplitting
Ok, what sort of design would be the most appropriate for beamsplitting a 532nm laser beam? The Glan-Taylor Prism is used for this purpose (as are others, but they aren't known as a "Laser Prism"), but what angle would I need to cut a piece of calcite on in order to get the angles right?
Presumably the angle of reflection can be worked out, but I've been reading around and it appears that the angles can be optimized for certain
wavelengths of light in order to get the O- & E-Beams 90' to each other (and thus easier to work with, avoiding mirrors).
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a_bab
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Look for the "beam splitter" inside of a CD unit (do a little reseach on this).
I know you need this for your Raman project, but if you start with crappy components the results will be the same or worse. You simply do not have the
technique to cut the calcite with enough accuracy (you'll need very fine surfaces, that would render a cleaner split light).
You have to look for a "splitting cube"; there are some costing around 20 bucks on ebay.
If your green laser is a pointer, then the results will be no better then here: http://pubs.acs.org/doi/abs/10.1021/ed800081t
[Edited on 30-3-2010 by a_bab]
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watson.fawkes
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Quote: Originally posted by a_bab  | | You simply do not have the technique to cut the calcite with enough accuracy (you'll need very fine surfaces, that would render a cleaner split
light). |
You can get this technique, though. It's not trivial, but certainly achievable. See Tim McCreight's
book The Complete Metalsmith, which has a section on faceting gemstones. The relevance of this is that angular accuracy is paramount in
getting four or more facets to meet at a point. And "cutting" isn't descriptive of the technique; it uses abrasives and a flat, rotating platen.
One other note. The angles you're looking for are relative to the optical axis of the material, not merely to each other. This means that you'll need
a way of getting initial alignment, one that (as I recall) isn't in the McCreight book.
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unome
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It's alright - I decided to go with a half-silvered (2-way) mirror - they are cheap as shit...
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mineralman
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JUST FOR INFORMATIONAL PERPOSES, Im a jewller and cut, shape and polish, both precious & semiprecious gemstones for 30+ yrs. So if anyone needs
info on any aspect of minerals & gemstons, from the moh (hardness) scale to the type of cutting/grinding wheel & best grit/polish powder or
equipment best used, just ask away.
I may even reveal a few secrets of the trade if your lucky
The cleavage line for Iceland spa follows a rhombohedron shape, if you held it up by it's two furthest points between your finger and thumb, that
would be your cleavage line.
but unless you have or know someone with a faceting wheel selection along with the unit to go with it as I do, I would give the same answers as have
allready been mentioned. MM
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chemrox
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I made holograms using cheap mirrors and beam splitters and they all worked. What was critical was getting a good sand table setup BELOW GROUND
SURFACE. I can't emphasize enough the importance of that.
"When you let the dumbasses vote you end up with populism followed by autocracy and getting back is a bitch." Plato (sort of)
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Texium
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Thread Moved
20-11-2023 at 12:16 |
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