DIC, Analyzers, and Compensators

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microb
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DIC, Analyzers, and Compensators

#1 Post by microb » Mon Feb 24, 2020 11:44 pm

Hi,

I'm slowly assembling some setups to make prisms from calcite and quartz. The goal here is to get DIC Nomarski prisms working and also quartz prisms/waveplates.

If any like minded folks can help over the next few months in getting some form factor details on microscope setup such as Olympus BX, Leica DMR, Nikon lab/opti/phot setups, please let me know. I do not want to spend a thousand on a used compensator, so If I can get some specs on the sizings and movements, any help would be appreciated. Plus also test procedures for things like thickness and pol angles. I'll set up a rig to get some cheap calcite sample mounted to dops at first. It's the softest to polish. I have some long one-inch diameter rods of synthetic quartz as well to try out.

Thanks,
Ted

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Re: DIC, Analyzers, and Compensators

#2 Post by wstenberg » Wed Mar 04, 2020 9:43 pm

Ted,
Exciting project.
Please post some photos.
Maybe we can all learn something from your efforts!

Good luck with it!
William
Astoria, Oregon

Zeiss Axiomat
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Nanonaut
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Re: DIC, Analyzers, and Compensators

#3 Post by Nanonaut » Fri Apr 03, 2020 2:20 pm

Hi Ted,

I can help you with BX, I can measure slots for components and send you the drawings, eg U-DICT, U-DICR, Condenser Prisms, etc.

microb
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Re: DIC, Analyzers, and Compensators

#4 Post by microb » Fri Apr 03, 2020 6:53 pm

Nanonaut wrote:
Fri Apr 03, 2020 2:20 pm
Hi Ted,

I can help you with BX, I can measure slots for components and send you the drawings, eg U-DICT, U-DICR, Condenser Prisms, etc.
Hi,

Any specs on the BX parts would be appreciated.

I've been focusing on the first of three parts 1) lapping and getting that process in place for calcite. I have the machine, but still talking with vendors on slurries and such. Best results will probably be with quartz, but trying the cheaper material first. I'll put protective glass on either side.

Then there are two other sides of this project not really addressed just yet. But I'll share examples of my yet to answer questions that may very well have trivial answers:

2) the dimensions of the prism and actual optical angle placement in a final prism. Given one wedge has an optical axis is going left-and-right, the other axis is pointing down the length of the prism but some references say perfectly perpendicular to the first and some show diagrams of it angled up a bit, but no numbers. I was going to look into the math and do birefringent raytracing to figure that out. Olympus has a web page showing a simulation of sorts. So something like that. I have the article where researchers measured the optical distance/angles of the two birefringent rays of the BX prisms. Need to go through that in more detail.

3) modeling the mounts and the actual prisms, which are probably quartz, so calcite would need a different form factor especially with optically glued glass sandwiching it for protection. The interference plane with its distance above the objective would seem to be a factor, so the distance the BX objective turrets have between the rms/25mm holder thread collar and the slide slot above would seem to be important, but I need to confirm that since other reflectance/metallurgical setups put the prism pretty much anywhere along the optical path. Transmission setups seem to always have objective specific prism holders, so maybe distance between objective back and prism is important even in infinity paths. I just thought the rays would be parallel, so the requirement would be limited to the lateral distance matching on both sides. But maybe I'm missing something.

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Re: DIC, Analyzers, and Compensators

#5 Post by Scarodactyl » Fri Apr 03, 2020 7:04 pm

I think you may find quartz easier to lap and polish. No cleavage, and cerium or zirconium oxide will produce a perfevt polish if the surface is well prepped. Is optical quartz proving to be that expensive?

microb
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Re: DIC, Analyzers, and Compensators

#6 Post by microb » Fri Apr 03, 2020 7:41 pm

Scarodactyl wrote:
Fri Apr 03, 2020 7:04 pm
I think you may find quartz easier to lap and polish. No cleavage, and cerium or zirconium oxide will produce a perfevt polish if the surface is well prepped. Is optical quartz proving to be that expensive?
It's not expensive. I just haven't found a supplier just yet. Some people in Silicon Valley are selling some synthetic quartz and I bought a batch, but they are long narrow crystals. Calcite can come in large blocks, so there are a bunch of different prism filters like lyot that I'd like to try out on down the road even if there are occlusions across a larger crystal. But yeah, I could get quartz running sooner. It is what Olympus is using. If you have info on the best lapping disc, I have a cast iron one -- not for calcite of course. It just came with the machine I got. I'm trying to get other discs right now but that was focusing on calcite. So yes, I could focus more on the quartz. If you know a supplier that doesn't just do thin disc wafers, please let me know.

Thanks,
Ted

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Re: DIC, Analyzers, and Compensators

#7 Post by Scarodactyl » Fri Apr 03, 2020 7:49 pm

Depends on your budget. Laps meant for faceting are expensive but might yield very good results. You can get ones with diamond sintered in that only need water cooling for the coarser grits, then finish with oxide on a polishing lap.

microb
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Re: DIC, Analyzers, and Compensators

#8 Post by microb » Sat Apr 17, 2021 6:00 pm

Scarodactyl wrote:
Fri Apr 03, 2020 7:04 pm
I think you may find quartz easier to lap and polish. No cleavage, and cerium or zirconium oxide will produce a perfevt polish if the surface is well prepped. Is optical quartz proving to be that expensive?
I got some ever so slightly larger quartz crystals.

So I think I can do something with these. Your know: doorstop, paperweight, or a permanent ice sculpture.
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microb
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Re: DIC, Analyzers, and Compensators

#9 Post by microb » Sat Apr 17, 2021 6:07 pm

Some quick optical axis tests:
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