Hello optics fans --

I picked up a large, surplus optical assembly a while back and am
finally getting serious about learning more about it. I'd especially
like help figuring out what the exotic lenses may be composed of.

Clearly a lab piece, with a heavy golden-toned tube, probably
aluminum. Looks aged but not ancient. It contains several lenses,
up to 5" in diameter, which appear to be mirrored but are actually
composed of a shiny, blackish substance opaque to visible light.
They are mostly meniscus, with faint purplish, reddish or bluish
sheens - which I presume are antireflection coatings.

Plate on the tube reads OSTI, which turns out to be a small division
of Telic optics (now part of Axsys) - a group that specializes in IR
optics. Faintly discernable on the tube is the name of a major
military contractor, so I assume we're talking defense rather than,
say, astronomical IR optics. No indication of focal length or such
stats that I can read, but some cryptic letters and numbers.

There is also a large flat 'filter' which is transparent and vivid
yellow in color. This was in the center of the assembly, between the
dark/mirror lenses.

From digging around on the web I am speculating that the yellow
'filter' may be ZiSe. If so I'm curious about its properties when
used as an apparent filter. I gather that it is often employed as a
focuser of IR light. (I do realize that, if I'm correct, it is a
fairly toxic -- though fortunately also rather inert -- substance.)

And the dark lenses - silicon or germanium perhaps? How could I
tell? I know that they are not just mirror-coated glass because a
small chip is broken off one; the broken surface is rippled like a
broken glass surface but opaquely shiny like a metal.

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Posted at:
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From:	stevelu
Subject:	re:Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	15 Jan 2005 01:30:26 -0600

whoops, that was me. (Share a machine, check the login status-es.)

So, yeah, not much to go on: just the labels on the big metal tube
(which focuses a bit). It is about 14" long, and has three sections:
two end pieces about 5 1/2" in diameter and a longer central tube more
like 6" across. An unlabeled scale with zero at the midline wraps
halfway around one end of the middle section. There is a small
cap/screw/vent that can be removed and a couple of hex wrench
adjustment points.

The official looking/manufacturing label is from OSTI, Optical
Systems and Technology Inc of Bedford Mass, with a serial number
("001"!) and model number.

The key is presumably the clear tape label, which has "B.S. #2-91% R"
on it. That must mean something to someone.

Oh yeah, and the other key may be the spot where a label was removed.
In the right light the letter RAYTHEON can still be made out in the
adhesive.

I found both Astro and Electrical Engineering refs searching under
'chopper infrared [etc]'.

Some sort of high-energy work, I presume.

Okay, I gotta ask, what are the odds this thing is hot? I.E.,
somewhere noticably above the background level in terms of
radioactivity? Assuming the folks who used it weren't nuts and took
reasonable care of their equipment, I mean. My boss suggested
testing it with proximity to a blank roll of film....

Thanks for your help, everyone.

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From:	Martin Rost
Subject:	Re: re:Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	Mon, 17 Jan 2005 13:47:14 -0500

"stevelu" wrote in message
news:41e8c692$1_2@Usenet.com...
>
>{SNIP}
> Okay, I gotta ask, what are the odds this thing is hot? I.E.,
> somewhere noticably above the background level in terms of
> radioactivity? Assuming the folks who used it weren't nuts and took
> reasonable care of their equipment, I mean. My boss suggested
> testing it with proximity to a blank roll of film....
>
> Thanks for your help, everyone.

There is a chance of some radioactivity from the AR coating on the optics,
depending on the age of the assembly. Thorium Fluoride used to be popular
for infrared AR coating designs.

Martin

From:	Mark W. Lund, PhD
Subject:	Re: Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	Sat, 15 Jan 2005 10:53:12 -0700

I suspect that this is part of a test set for infrared optics,
a collimator for testing FLIRs, seekers or rangefinders.
That would explain why it is serial number one, and
justify why it is so large.

This thing is highly poisonous and radioactive,
you had better send it to me so I can play with it, oops
I mean dispose of it properly!:)

Best regards
mark

stevelu wrote:
> whoops, that was me. (Share a machine, check the login status-es.)
>
> So, yeah, not much to go on: just the labels on the big metal tube
> (which focuses a bit). It is about 14" long, and has three sections:
> two end pieces about 5 1/2" in diameter and a longer central tube more
> like 6" across. An unlabeled scale with zero at the midline wraps
> halfway around one end of the middle section. There is a small
> cap/screw/vent that can be removed and a couple of hex wrench
> adjustment points.
>
> The official looking/manufacturing label is from OSTI, Optical
> Systems and Technology Inc of Bedford Mass, with a serial number
> ("001"!) and model number.
>
> The key is presumably the clear tape label, which has "B.S. #2-91% R"
> on it. That must mean something to someone.
>
> Oh yeah, and the other key may be the spot where a label was removed.
> In the right light the letter RAYTHEON can still be made out in the
> adhesive.
>
> I found both Astro and Electrical Engineering refs searching under
> 'chopper infrared [etc]'.
>
> Some sort of high-energy work, I presume.
>
> Okay, I gotta ask, what are the odds this thing is hot? I.E.,
> somewhere noticably above the background level in terms of
> radioactivity? Assuming the folks who used it weren't nuts and took
> reasonable care of their equipment, I mean. My boss suggested
> testing it with proximity to a blank roll of film....
>
> Thanks for your help, everyone.
>
> *-----------------------*
> Posted at:
> www.GroupSrv.com
> *-----------------------*

--
----------------------------------------------------------------------
Mark W. Lund, PhD ** Battery Chargers
CEO ** Bulk Cells and Custom Battery Packs
PowerStream Technology ** Custom Power Supplies
140 S. Mountainway Drive ** DC/DC Converters
Orem Utah 84058 ** Custom UPS
http://www.PowerStream.com ** Engineering, manufacturing, consulting

From:	Joe Rongen
Subject:	Re: Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	Sat, 15 Jan 2005 15:35:46 -0500

"Mark W. Lund, PhD" wrote
in message news:41e96525$1@news.mcleodusa.net...

> I suspect that this is part of a test set for infrared optics,
> a collimator for testing FLIRs, seekers or rangefinders.
> That would explain why it is serial number one, and
> justify why it is so large.

Possible, thought I would rather guess with a number
like that - it logically must be from AirForce One?

Most likely those IR parts were used to see through
a lot of BS and spot the new public menace: people
with awfully green lasers. :-)

From:	stevelu
Subject:	re:Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	15 Jan 2005 02:30:40 -0600

coupla final notes for the evening:

Those metallic lenses are quite noticably heavier than glass.
Consistent with Germanium but not I presume with anything made mostly
from Silicon. Any other possible compositions I should consider?

The flat yellowish filter, which did have an acrid whiff, which I took
to be sulpherous, when I first took the covering lens off it, may be
as much orangish as yellowish. kindof a golden color, at least in
some light.

Steve

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From:	stevelu
Subject:	re:Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	14 Jan 2005 19:31:02 -0600

Thank you, Phil.

ZnSe is orange, and ZnS is yellow

That would explain the smell when I took that piece out!

No, seriously. I just saw ZnSe described as yellowish and clear and
part of systems focusing non-visible light, and didn't even know to
look for ZnS - therefore didn't know how to interpret that bit of
informal molecular analysis. Hazards of casual online research.
Just as well I don't have a chunk of Selenium in my garage.

So, what kind of wavelength filtering or other beneficial effect would
one expect to gain from combining a ZnS flat with Si or Ge lenses?

(as you can see, it's too late to follow the advice about not taking
the assembly apart, though I did stop before I had took all the
elements out, and that plus the fact that they are of different
diameters means there's a very good chance I can reassemble them in
original sequence 8^)

So, with the question of Si, Ge, or both still unresolved for now, for
the remainder of the elements, would anyone like to speculate what
this marvelous device might have been intended to do?

a) focus a laser
b) imaging of some kind
c) basic research into fundamental principles of IR optics
d) both a and b
e) both a and c
f) a, b, and c
g) something else
h) "some things man was not meant to know"

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Posted at:
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From:	Skywise
Subject:	re:Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	Sat, 15 Jan 2005 20:46:30 -0000

sp_lussier@yahoo-dot-com.no-spam.invalid (stevelu) wrote in news:41e87256$1_2
@Usenet.com:

> a) focus a laser
> b) imaging of some kind
> c) basic research into fundamental principles of IR optics
> d) both a and b
> e) both a and c
> f) a, b, and c
> g) something else
> h) "some things man was not meant to know"

i) none of the above

:)

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy

Sed quis custodiet ipsos Custodes?

From:	Joe Rongen
Subject:	Re: re:Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	Fri, 14 Jan 2005 21:14:07 -0500

"stevelu"
wrote in message news:41e87256$1_2@Usenet.com...
.....
> So, with the question of Si, Ge, or both still unresolved for now, for
> the remainder of the elements, would anyone like to speculate what
> this marvelous device might have been intended to do?

Did you not find any indication for a chopper, detector or source?

From:	Phil Hobbs
Subject:	Re: Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	Fri, 14 Jan 2005 17:14:54 -0500

ZnSe is orange, and ZnS is yellow.

The lenses might be either Si or Ge--they look pretty similar. If I had
it in my lab, I'd sit it in front of my (incandescent) desk lamp, and
check if I could see through it with a 1.3-um IR viewer. If so, they're
all Si. If not, at least one is Ge. You won't want to disassemble it,
but the quite different densities of Si and Ge are another way of telling.

Cheers,

Phil Hobbs

From:	J&E
Subject:	Re: Non-visible-light/IR focusing lenses-Si, Ge, ZiSe?
Date:	Fri, 21 Jan 2005 18:18:14 -0600

Pictures really are worth a thousand words. Post the numbers, too.

Some anodized aluminum is a goldish color.

Maybe the "B.S." refers to a beam splitter, if there is another port?

Where'd you get it?