From: 
To: Paul Cousoulis ,
Reply-To: 


Here is the information requested for references to holographic objective
lens information.

The author is Dr. Murty V. Mantravadi, Optical Shop testing 2nd Edition.

Start Quote
"After all a hologram is a special diffraction grating and hence it
splits colors just like a diffraction grating. Therefore, it can never be
used to form images in white light except in very special situations of
construction. But if you want to replicate an equivalent of a lens or a 
concave mirror , the resulting hologram has very large amount of chromatic
aberration. When we use lenses, we can choose two different glasses and
make an achromat. The two glasses are usually crown and flint with
V-numbers of 60 and 30 respectively. Every holographic lens or mirror has a
V-number of about -3 to -4 and if we try to obtain an achromatic
holographic lens or mirror  by using a positive and negative lens
equivalents, we cancel out the the powers and end up with zero power lens.
         Regarding projecting a hologram, it can be done. But most of the
holograms are made to show behind the plane. When you want to project a
real 3-D image out in space, the cone of light should be very large so that
 the eyes can receive the light from the image. Most of the time this does
not happen. You need a diffusing medium just like a screen in the movie
theater. In the case of a 3-D real hologram, we need to  project the image
into a diffuse medium of some depth. This medium could be a chamber with
very fine suspended transparent particles. I do not know anybody has done
this but this is one way.
            Regarding the statement that the holgram is formed by the
interaction of front and back surface reflections, it is not correct as you
know. The hologram is the result of difracted light from the very fine  and
highly complex and nonlinear line grating structure.
     I do not understand what they mean by the image at the edge of the paper.
*******************************************************************************
*************************************
       If you want, you can communicate the above. But generally, the e-mail
discussion  never ends  and after a while one gets tired. It is better to
deal with these things in a real face to face discussion. Murty"
End Quote


> From: 
> Date: 2003/07/02 Wed PM 09:21:45 PDT
> To: Paul Cousoulis , 
> Subject: ATM Holographic Objective Lens?
>
>
> Hi Paul,
> Sure, always glad to do more than just lurk.
>
> I'll post again tomorrow but the link you provided has the following:
>
> Optical Devices--Holographic lenses, diffraction gratings, etc.These are
holograms in which the "object" is a mirror or a lens.A flat
mirror as an object produces a diffraction grating. A lens or a concave
mirror as the object produce a hologram that behaves LIKE A LENS! These
HOLOGRAPHIC LENSES are lighter than traditional lenses and mirrors and they
can be designed to perform more specialized functions such as making the
panel instruments of a car visible in the windshield for enhanced safety.
>
> Take care and keep us thinking you guys :)
> Peter Nance, Jr.
>
> >
> > From: Paul Cousoulis 
> > Date: 2003/07/02 Wed PM 07:52:04 PDT
> > To: atm{at}shore.net
> > Subject: Re: ATM Holographic Objective Lens?
> >
> >
> > This is the website that convinced me of my error.
> >
> > http://members.aol.com/gakall/holopg.html
> >
> > Paul
> >
> > Dave Magee wrote:
> > >
> > > Pete,
> > >
> > > I hope you'll at least give the rest of us the documentation
reference to
> > > back up what you say.
> > >
> > > /Dave
> > >
> > > > > 1. Holographic lenses have already been built.
> > > > >
> > > > > 2. The major problem is the chromatic abberations.
> > > > >
> > > > > 3. Thats all I care to comment on this subject.
> > > > >
> > > > > Best regards,
> > > > > Pete Nance, Jr.
> >
> >
>
>
>

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