HDTenEightyP/NetNews huggingface dataset:
From: jrm@gnv.ifas.ufl.edu
Newsgroups: sci.optics
Subject: Re: Diode Laser Holograms ?
Date: 11 Sep 92 23:28:19 GMT

In article <nsvny9+@lynx.unm.edu>, dinsdale@chtm.eece.unm.edu (Don McDaniel) writes:
> In article <1992Sep10.190056.1651@gnv.ifas.ufl.edu> jrm@gnv.ifas.ufl.edu writes:
>>In article <BuCGMp.L0o@bunyip.cc.uq.oz.au>, coates@newton.physics.uq.oz.au (Tony Coates) writes:
>>> I think that you will find that diode lasers tend to have a
>>> coherence length of around 30cm or 50cm or the like, which
>>> means that all the path lengths for the holograms would have
>>> to be kept rather short.  Whether this is impossibly short
>>> depends on the specifics of the hologram setup, of course.
>>> 
>>> 						Tony.
>>
>>	Thanks for this info. A 50cm coherent length need not be
>>	fatal - just have to keep the whole setup small (which
>>	may translate into cheap & convenient). My interest is
>>
> I think you'll find a further problem (beyond coherence length) in
> trying to use a diode laser.  Unless you get your hands on a vertical
> cavity laser (they're not very powerful yet), the severe astigmatism
> of the output will make collimation of the beam difficult.
> 
> The best way to get a reasonable beam is by using an anamorphic prism
> pair to correct the astigmatism.  Good ones are quite expensive which
> [...]
> Finally, I think the estimate of 30-50 cm coherence length is a bit
> generous for many devices, particularly the higher power ones which
> tend to have somewhat broader linewidth's (than quarter-wave-shifted

	You really know how to cheer-up a person :-)

	I did not realize there was such a severe astigmatism prob
	with the diode lasers. Hmmm ... wonder if they could build
	in corrective optics during manufacture - I guess not unless
	a big market develops. (holo-TV ?)

	One question about the relevance of coherence length. I seem
	to recall that crude holograms had been made well prior to
	the invention of the laser - normally using one of the lines
	from a mercury arc. While the quality wasn't good, they still
	got a hologram. So, MUST holograms be made with coherent 
	light or will well-collimated monochromatic light do ? I admit
	my memory on this may be defective. Perhaps they ran the
	light thru a long optical path replete with lots of pinholes
	to try and isolate just a speck of 'good' light ?

-- Jim Mason
Newsgroups: sci.optics
From: clarke@acme.ucf.edu (Thomas Clarke)
Subject: Materials for Holographic Optical Elements
Organization: University of Central Florida
Date: Tue, 8 Sep 1992 15:25:40 GMT

I am looking for an easy to use material that
can be coated onto a substrate and used for recording
volume holograms in order to make HOEs.

The "Holography Handbook" mentions a two-part photo polymer
made by duPont.  Can anyone supply a pointer to this?  Are
there any other similar materials?

Are there kits that make it easy coat and use dicromated
gelatin?

Am I wishing for the moon?

--
Thomas Clarke
Institute for Simulation and Training, University of Central FL
12424 Research Parkway, Suite 300, Orlando, FL 32826
(407)658-5030, FAX: (407)658-5059, clarke@acme.ucf.edu
Newsgroups: sci.optics
From: swami@sauron.eece.unm.edu (Swami srinivasan)
Subject: Index of TEFLON @ 86 GHz
Date: Thu, 10 Sep 92 23:55:54 GMT
Organization: University of New Mexico, Albuquerque
Followup-To: lwang@bootes.unm.edu swami@triton.unm.edu



    We need to know the refractive index of TEFLON at 86 GHz. 

This  is required for dielectric waveguide design. Info on absorption
coefficient will also be very useful.

Any pointers to relatively high-index dielectrics @ 70 - 100 GHz?

	Thanks for any and all replies!

						    swami

====================================================================
swaminathan srinivasan
center for high tech materials
eece, university of new mexico
albuquerque, nm 87131			swami@chtm.eece.unm.edu
===================================================================


Newsgroups: sci.optics
From: knapp@spot.Colorado.EDU (David Knapp)
Subject: Re: Diode Laser Holograms ? 
Organization: University of Colorado, Boulder
Date: Thu, 10 Sep 1992 14:37:34 GMT

In article <1992Sep9.185940.1647@gnv.ifas.ufl.edu> jrm@gnv.ifas.ufl.edu writes:
>OK now, I have heard conflicting reports from dubious sources, so can
>anyone here answer me one question --- ARE DIODE LASERS SUITABLE FOR
>MAKING HOLOGRAMS ?

Perhaps, but if so, it would not be easy or high quality.

>If not, why not ?


I believe that it simply boils down to coherence  length. This is proportional
to the 'cavity length' which the diode has very little of.  Hopefully Prof.
Siegman will answer this post as he is perhaps the best qualified  person
on the internet to do so.


>If so, are any special specs or
>techniques required ? As the price of high-powered diode lasers comes
>down rapidly, it would sure be nice to be able to use them for this
>purpose. Already we get a 10:1 power/price advantage over gas lasers
>in the 2-30 mw zone. 
>
>One other question ... does anyone know a source for *affordable*
>fresnel lenses with negative FLs ? I'm looking for the kind done
>in hard plastic, not those PVC window-stickups. Edmund only seems
>to sell posivive FL lenses in the hard plastic.
>
>-- Jim Mason


-- 
David Knapp                                      University of Colorado, Boulder
Perpetual Student                                   knapp@spot.colorado.edu
Newsgroups: sci.optics,sci.astronomy
From: lhawkins@olaf.wellesley.edu (Lee Hawkins)
Subject: Celestar (sp?) of Kansas?
Organization: Wellesley College
Date: Mon, 14 Sep 1992 15:06:21 GMT

I am trying to locate a used optics dealer in Kansas called Celestar
(sp?).  All I know is that they deal in World War II vintage 
surplus sextants and other optics.  Can anyone supply an address/phone
number?

Thanks in advance,
--Lee
________________________________________________________________________________
R. Lee Hawkins					 lhawkins@annie.wellesley.edu
Department of Astronomy				 lhawkins@lucy.wellesley.edu
Whitin Observatory
Wellesley College                                   Ph. 617-283-2708
Wellesley, MA 02181                                 FAX 617-283-3642
________________________________________________________________________________
From: murtza@andromeda.rutgers.edu (SANDMAN)
Newsgroups: sci.optics
Subject: QUESTION ?
Date: 15 Sep 92 23:46:47 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

I was just wondering last night that if anti-noise technology can be used 
to decrease noise can't anti-light be produced as light is also thought 
to have wave characteristics ?

Please answer.

Shamoun Murtza


-- 
*DEATH TO THE 'DUSHAMNS' OF PAKISTAN		* SHAMOUN MURZTA              *
*WHO SAYS THAT I AIN'T RIGHT . . . .		* RUTGERS UNIVERSITY	      *
*LIFE IS FOR MY OWN TO LIVE MY OWN WAY		* PH: (201) 997-2685          *
*				-METALLICA     	* PAKISTAN ZINDABAD.	      *
Newsgroups: sci.optics
From: bunner@vms.macc.wisc.edu (Dana A. Bunner)
Subject: Re: High Index glasses
Organization:  University of Wisconsin Academic Computing Center
Date:  5 SEP 92 18:09:53    

In article <1992Aug28.191721.12165@odin.corp.sgi.com>, rodman@pkr.asd.sgi.com (Paul Rodman) writes...

>Polycarbonate high-index glasses seem to have more problems with field 
>distortion (i.e. warping of the field at the edges) and with chromatic
>distortion (prismatic splitting of light sources shining through near the
>edges). 

Agreed.  I have a polycarbone HI set and they exhibit severe chromatic
distortion ... and the image doesn't have to be too far out from center
before it starts showing.

>Newer types don't seem to suffer as much from these problems, but can still
>suffer from distortion. 

Again I concur.  My new lenses are far superior to the polycarbs, which are
still sold by several eyeglass retailers.  With my second pair of H.I., I 
selected frames which were smaller and more rounded.  This lessened the 
distortion/chromatic effects.  A large, square frame polycarb
reduced my usable field of view dramatically.  NOT RECOMMENDED!

>Try this experiment: Turn your head 30 degrees to the right of your 
>computer screen, look at the screen without turning your head and see how 
>sharp the characters are... Do the same to the left. 

No question, there is a distinct loss of clarity.  

>I am surprised and baffled at my problem but have decided to avoid high-index
>plastics now and in the future until I can find out more about the subject and
>the whole manufacturing process.

The choice between heavy 6+ diopter glass lenses and "fuzzy edged" high index
is a lose-lose situation for me.   After using the polycarb H.I. lenses, the
second set is a real relief, but still optically 2nd rate to standard glass.

And 6 of 7 eyeglass retailers made absolutely no mention of the H.I. problems
during my last purchase process.  Even after broaching the subject myself, two
denied any problems and chalked up my experience to getting a "poorly ground
lense".  

Dana Bunner
From: loki@castle.ed.ac.uk (A Kashko)
Newsgroups: sci.optics
Subject: Glass grinding
Date: 10 Sep 92 11:30:38 GMT
Organization: Edinburgh University


	I have been translating an article on glass grinding, and came across
a statement that currently used grinding solutions contain 30% of glycerine.
The word used could also translate as glycerol. Our library here has nothing
on glass grinding

	Could someone please email me as to whether grinding solutions contain
glycerin or glycerol. Preferably soon.

		Thanks in advance.
From: jrm@gnv.ifas.ufl.edu
Newsgroups: sci.optics
Subject: Re: Diode Laser Holograms ? 
Date: 11 Sep 92 22:32:47 -0500

In article <1992Sep11.220753.27720@sfu.ca>, palmer@sfu.ca (Leigh Palmer) writes:
> In article <1992Sep10.190056.1651@gnv.ifas.ufl.edu> jrm@gnv.ifas.ufl.edu
> writes:
>>In article <BuCGMp.L0o@bunyip.cc.uq.oz.au>, coates@newton.physics.uq.oz.au
> (Tony Coates) writes:
> 
>>        One 'fringe' use of holos that does interest me very much
>>        is how the holos can emulate the actions of real lenses
>>        that are holographed. I also note that computers can now
>>        (cheaply) calculate interference patterns which can be
>>        used to make holos of totally computer-generated objects.
>>        Think of making a corrector plate so a heads-up display
>>        could be projected onto the windshield of any given model
>>        of automobile. Pressing or grinding real lenses to counter      
>>	  [...]
>>        This months issue of 'Scientific American' has a short review
>>        article that indicates that very cheap IR imaging arrays may
>>        soon be availible. Imagine laying the IR image over the wind
>>        screen at night using cheap heads-up optics. Visibility
> 
> A nice idea; the clock's running on your year to patent it. I'll add
> my own twist: by making a conventional hologram using an actual 
> windshied one might be able to get an even simpler production method.
> There is an article on computer generated holography using a laser
> printer as output device in the current American Journal of Physics
> (September 1992, p. 839) via the phase detour method. The intensity 
> problem you mention is inherent in that method, but in the method I
> propose phase holograms, which do not have the intensity problem, can
> be made.

	I will look-up that article. Thanks for this info. I'm not
	sure if a regular laser-printer can do a good enough job
	to make an actual (worthwhile) hologram though. Maybe for
	the far infrared ? Now there are some laser -> film
	recorders that probably *can* draw tight enough lines to
	be useful at visible wavelengths. 

	I had forgotten all about phase holograms. That would indeed
	get around the brightness problem in the simulated optics. 
	Any transparent material which could have its refractive
	index changed locally by applying heat would do a good job
	at this task. I'm sure the optical computer-disk people
	have done a wealth of research into materials like these.

	It's hopeless for me to try and patent things like the
	IR/auto heads-up idea. The military must be doing this
	already since it is such a logical thing to do. Could
	easily replace those nasty narrow-angle goggles. Take
	a binocular image and just use the cheap polarization
	method for 3-D viewing and a pilot would have difficulty
	discerning the real image from the IR ... depth perception
	would be preserved, or maybe even enhanced. Besides, I
	thought of using liquid-crystals for a self-darkening
	welders visor years before any hit the market ... I just
	have bad luck in these things.

-- Jim Mason
From: jimbo@ee.ualberta.ca (Row Jimmy)
Newsgroups: sci.optics
Subject: high power 670nm diode lasers?
Date: 9 Sep 92 15:37:22 GMT
Organization: University Of Alberta, Edmonton Canada

greetings all,

i am currently attempting to find a supplier of high power visible laser
diodes. if possible i would like devices of 10mW or greater. i believe that
toshiba manufactures such a device as may hitachi/NEC or sharp but i am 
having (the usual) difficulties finding a supplier who is both knowledgeable
and helpful. can anyone out there in the vast expanse of the internet lead
me to someone who can help me?

thank you for your help,

			jim (sometimes the light's all shinin' on me...
			     ... other times i can barely see.)


-- 
Jim Bauer                               jimbo@ee.ualberta.ca
Medical Laser Lab                       alberta!bode!jimbo
University of Alberta 136 Civil Elect   Voice (403)492-1489
Edmonton, Alberta Canada  T6G 2G7       Fax   (403)492-1811
Newsgroups: sci.optics
From: jmcvey@boi.hp.com ( John McVey         x3638 )
Subject: Need phone number of  Jaeger optics
Date: Tue, 8 Sep 1992 15:35:12 GMT
Organization: Hewlett-Packard / Boise, Idaho
X-Newsreader: Tin 1.1scd1 PL4

 A. Jaegers, 6915 Merrick Rd.i, Lynbrook, NY 11563
            516-599-3167

John McVey
jmcvey@hpbslq.boi.hp.com
Newsgroups: sci.optics
From: ka1gt@cbnewsm.cb.att.com (robert.m.atkins)
Subject: Negative Achromats - where to find?
Organization: AT&T
Distribution: na
Date: Fri, 11 Sep 1992 19:16:02 GMT

I'm looking for a source of negative achromats. I'm interested in something
with a diameter of 40-50mm and a (negative) fl around 100mm or so. I've
checked out a few sources (Edmunds, Spindeler & Hoyer, Melles Griot) but
non of them have much of a selection, and nothing in the range I'm looking
for. Any suggestions as to who might have a wider product line of this type
of lens (Multi AR coated if possible)?

===============================================================
Bob Atkins  AT&T Bell Labs  email (direct)  att!clockwise!rma
===============================================================
From: habersch@husc9.harvard.edu (Oren Haber-Schaim)
Newsgroups: sci.optics
Subject: slide projectors cannot produce collimated light
Keywords: projectors, collimated light
Date: 7 Sep 92 02:05:28 GMT
Followup-To: can slide projectors produce collimated light
Organization: Harvard University Science Center


     In article <1992Sep4.205510.22755@athena.mit.edu> wtsang@athena.mit.edu
     (Pui Ho Wilson Tsang) writes: 
     >The title says it all.  Thanks.


The responding title says it all too.  You're welcome.
Newsgroups: sci.optics
From: minsky@media.mit.edu (Marvin Minsky)
Subject: Re: Slide projectors can too produce collimated light!
Organization: MIT Media Laboratory
Date: Tue, 8 Sep 1992 20:15:29 GMT

In article <ZOWIE.92Sep7214451@daedalus.stanford.edu> zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes:
>In article <QeeszQe00WBNQ2NXw_@andrew.cmu.edu> mw4j+@andrew.cmu.edu writes:
>  <stuff deleted>

>[Of course, you *do* need to put a pinhole at the focal plane to get the
>collimated light -- so you end up throwing out most of the radiance...]

Perhaps you can move the "condenser" lens, if there is one, to focus
the lamp filament on the pinhole (which then better be made of
heat-resistant metal.  With luck, this will increase the output
radiance by factor of 100-1000 or so.

Newsgroups: sci.optics
From: palmer@sfu.ca (Leigh Palmer)
Subject: Re: Diode Laser Holograms ? 
Organization: Simon Fraser University
Date: Fri, 11 Sep 1992 22:07:53 GMT

In article <1992Sep10.190056.1651@gnv.ifas.ufl.edu> jrm@gnv.ifas.ufl.edu
writes:
>In article <BuCGMp.L0o@bunyip.cc.uq.oz.au>, coates@newton.physics.uq.oz.au
(Tony Coates) writes:

>        One 'fringe' use of holos that does interest me very much
>        is how the holos can emulate the actions of real lenses
>        that are holographed. I also note that computers can now
>        (cheaply) calculate interference patterns which can be
>        used to make holos of totally computer-generated objects.
>        Think of making a corrector plate so a heads-up display
>        could be projected onto the windshield of any given model
>        of automobile. Pressing or grinding real lenses to counter      
>        the distortion from the curving windscreen would be rather
>        expensive - and could get impossibly so it one tried to
>        keep up with all the model-year variations. On the other
>        hand, using a holo to emulate these weird-shaped optics
>        and using a computer to calculate & produce these holos
>        would mean a great savings in money and time plus essentially
>        infinite flexibility in coping with new products. The
>        holo optics would be dimmer - but in an auto, plane or other
>        heavy conveyance this would be no big deal. 
>
>        This months issue of 'Scientific American' has a short review
>        article that indicates that very cheap IR imaging arrays may
>        soon be availible. Imagine laying the IR image over the wind
>        screen at night using cheap heads-up optics. Visibility
>        would increase nearly to daytime levels (in black & white 
>        only however) yet warning lights and such ccould still be
>        seen easily thru the glass. Just hazarding a guess, but I
>        believe that such an arrangement would become mandated by
>        law in almost every nation. [ This idea free to anyone who
>        wants to steal it ] The profits to anyone involved in making
>        parts for such systems would be incredible.

A nice idea; the clock's running on your year to patent it. I'll add
my own twist: by making a conventional hologram using an actual 
windshied one might be able to get an even simpler production method.
There is an article on computer generated holography using a laser
printer as output device in the current American Journal of Physics
(September 1992, p. 839) via the phase detour method. The intensity 
problem you mention is inherent in that method, but in the method I
propose phase holograms, which do not have the intensity problem, can
be made.

Leigh
Newsgroups: sci.optics
From: wtsang@athena.mit.edu (Pui Ho Wilson Tsang)
Subject: can slide projectors produce collimated light
Keywords: projectors, collimated light
Organization: Massachusetts Institute of Technology
Date: Fri, 4 Sep 1992 20:55:10 GMT

The title says it all.  Thanks.
Newsgroups: sci.optics
From: zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest)
Subject: Slide projectors can too produce collimated light!
Organization: Stanford Center for Space Science and Astrophysics
	<1992Sep6.220529.15423@husc3.harvard.edu>
	<mcdonald.284@aries.scs.uiuc.edu> <QeeszQe00WBNQ2NXw_@andrew.cmu.edu>
Date: 7 Sep 92 21:44:51

In article <QeeszQe00WBNQ2NXw_@andrew.cmu.edu> mw4j+@andrew.cmu.edu writes:

   Yeah, but you can't focus a slide porojector's lens at infinity, which
   you would need to do to get collimated light. That's the whole point of
   a projector - to project an image onto a new focal plane.

Depends on the projector, but most projectors (and *all* that I've seen)
have enough travel in the lens to permit focus at infinity.  It's cheaper to
make a system with big tolerances and extra travel than one that stops
*exactly* at infinity.  

[Of course, you *do* need to put a pinhole at the focal plane to get the
collimated light -- so you end up throwing out most of the radiance...]

This is the same kind of effect that lets you use a pair of binoculars as
a projection telescope:  since the focussing system is designed to produce
near-parallel rays, you can make them divergent (for direct viewing) or 
convergent (for projection).  Useful for looking at solar eclipses, and 
for impressing passers-by.
--
zowie@banneker.stanford.edu  "Tell your senator to fund the MSSTA program!"

 The world would be much better if more physicists read Strunk and White, 
 and if more fuzzies read Tipler.   *Everyone* should read and understand
 at least one economics text.  No exceptions.       -- zowie
Newsgroups: sci.optics
From: haferman@icaen.uiowa.edu (Jeff Haferman)
Subject: Wanted:  optical constants for LEXAN
Date: Tue, 15 Sep 1992 16:40:04 GMT
Organization: University of Iowa, Iowa City, IA, USA


  We have reviewed several optics handbooks and done a literature
  search in JOSA and Applied Optics to find values of the complex
  refractive index for LEXAN (polycarbonate).  Some limited values
  have been found, but nothing extensive.

  We are interested in the region 0.5 microns through about 100 microns,
  for a temperature range of about 20 degrees C to about 100 degrees C.

  Any pointers to a source for this information would be very
  appreciated!!

  Thanks in advance.


Jeff Haferman                            internet: haferman@icaen.uiowa.edu
Department of Mechanical Engineering     DoD 0186  BMWMOA 44469  AMA 460140
The University of Iowa
Iowa City, IA  52242                                 '76 R90S
Newsgroups: sci.optics
From: palmer@sfu.ca (Leigh Palmer)
Subject: Re: Slide projectors can too produce collimated light!
Organization: Simon Fraser University
Date: Thu, 10 Sep 1992 00:39:39 GMT

In article <1992Sep8.201529.7201@news.media.mit.edu> minsky@media.mit.edu
(Marvin Minsky) writes:
>In article <ZOWIE.92Sep7214451@daedalus.stanford.edu>
zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes:
>>In article <QeeszQe00WBNQ2NXw_@andrew.cmu.edu> mw4j+@andrew.cmu.edu writes:
>>  <stuff deleted>
>
>>[Of course, you *do* need to put a pinhole at the focal plane to get the
>>collimated light -- so you end up throwing out most of the radiance...]
>
>Perhaps you can move the "condenser" lens, if there is one, to focus
>the lamp filament on the pinhole (which then better be made of
>heat-resistant metal.  With luck, this will increase the output
>radiance by factor of 100-1000 or so.

I apologize for entering in mid-thread, but if my inference is correct then you
are being advised to try something which will not improve your result but may
do harm to your slide projector. I suspect the "luck" you need will be that you
must violate the second law of thermodynamics to improve your intensity.

I will assume that the "pinhole" refered to above is large enough in diameter
that its central Airy disk is no larger than the projection lens, since there
is no point to making it smaller; that will only cost intensity and you will be
diffraction limited instead by the projection aperture beyond that point.

While you may, indeed, increase the exitance from the pinhole by the artifice
of "moving" the inflexibly mounted condenser lens, you cannot increase the
exitance per unit solid angle in the direction of the projection lens; you can
only increase the solid angle itself.

I consider myself an expert in this particular area, by the way. I wasted a
couple of months of my PhD program trying to beat the second law in the design
of a far infrared monochromator! :<)

Leigh Palmer
Newsgroups: sci.optics