Telecom-style ND filters?

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Hi, all,

I need some ND filters for a stabilized laser product I'm designing.
Ideally it would be about 5 mm in size and less than 1 mm thick.

The fallback position is to use a polarizer, which I can get in that
size, but I'd far prefer to pick a density and stick to it.

Oh, and it needs to be stable to ~10 ppm at 70 C over time scales of hours.

Any bright ideas?

Thanks

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Re: Telecom-style ND filters?

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I sure don't see any smaller than 12.5mm at the places I can think of to
look. sciplus has a 6mm red, but no detailed specs on it (but it's also
too thick at 1.4mm) and it's not neutral density....and I find UK and
German companies that claim to do custom filters.

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A 5mm i.d. tube, some carborundum, water, putty to make a ring dam, a
drill press, and a 2x2" or 1" round filter, depending what you can find
that you like?

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

Re: Telecom-style ND filters?
On 08/10/2011 08:46 PM, Ecnerwal wrote:
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At 0.6 mm thickness, I can cut it with dikes if I have a few tries.
It's the thickness that's the real issue.

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Re: Telecom-style ND filters?

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Why not a partially transmitting metallic coating?

--

Sam

Conservatives are against Darwinism but for natural selection.
Liberals are for Darwinism but totally against any selection.

Re: Telecom-style ND filters?
On 08/11/2011 01:00 AM, Salmon Egg wrote:
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Sure thing, but it's for a product, and I need it soonish.  Some nicely
metallized Kapton would be the bee's knees.

Thanks

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Re: Telecom-style ND filters?
On Aug 10, 6:59=A0pm, Phil Hobbs
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I've got some plastic ND filter material. (made for theatrical
lighting by Tiffin) It's only 4 mils (0.1mm) thick.   It works out to
795 nm, but I haven=92t tested it beyond that.  I think it=92s some sort
of emulsion?   and it gets =91flaky=92 at high power densities.  I don=92t
think it will meet your 10 ppm spec, but I=92d be happy to stick a few
pieces in an envelope and you can try it.

George H.

Or evaporate metal onto a microscope cover slip?

Re: Telecom-style ND filters?
On 08/11/2011 10:27 AM, George Herold wrote:
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Thanks, George, that would be great.

Theatrical lights are pretty warm, so that should survive 85C okay.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Re: Telecom-style ND filters?
On 08/11/2011 10:27 AM, George Herold wrote:
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One of these times I'm going to have to get an evaporator, but the
cheapest decent ones are around $15k, so it won't be today.  At my PPOE
I had an old Denton DV502A whose vacuum gauge used a 12AX7A.  It worked
fine after I replaced the hivac valve, but I couldn't fit it in my
briefcase when I left. ;)

The filter material arrived today, thanks.  It works pretty well at 1
um, at least as measured with a 1 um longpass filter and a lead salt
vidicon camera  (which was $279 on eBay minus a lens, and works
perfectly with a 35 mm camera lens and an adapter).

What I'd like to have used was a piece of double-side polished silicon,
but all my wafer boxes stayed behind too.

Cheers

Phil Hobbs



--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Re: Telecom-style ND filters?

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I don't know what the process for getting one is, but a friend at a
university mentioned that a vacuum deposition system was on the used
equipment list (for free, I had to have a stern talk with myself) when I
asked about possible used fiber splicers. I could ask her to put the
appropriate people in touch with you, if you like (it's a not
unreasonable drive from your current locale.)

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

Re: Telecom-style ND filters?
On 08/16/2011 12:08 AM, Ecnerwal wrote:
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Thanks, Lawrence, that would be fairly cool.  I actually have enough
space to put it in at this point, so if it doesn't need too much TLC, it
might be a real win.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Re: Telecom-style ND filters?
On Aug 15, 10:45=A0pm, Phil Hobbs
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The tube was open to the vacuum?  That sounds like a cheap vacuum
gauge.

George H.

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Re: Telecom-style ND filters?
On 08/21/2011 10:45 AM, George Herold wrote:
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No, it was the amplifier for a thermocouple gauge.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net

Re: Telecom-style ND filters?
On Aug 21, 2:11=A0pm, Phil Hobbs
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I don=92t
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Oh, A Pirani gauge?  I've always wanted to build one of those.

George H.

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