Holographic polarizers

[P3D Greg Erker <erker@xxxxxxxxxxxxxx>]

Saw this in sci.optics:

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> I am trying to locate Information about linear-polarisers.

Looks like you are referring to so-called "sub-wavelength gratings".

A diffraction grating functions as a polarizer, if the grating
periodicity is smaller than the wavelentgh. If you think in terms of
lines per mm, that's more than 2500 lines per mm in the visible
region. Then the light does not "see" the grating and passes
through/reflects without diffraction. Only the state of polarization
is changed.

By optimizing the groove shape and depth, we can design and produce a
polarizer to your specifications. Single elements tend to become
costly in the visible region, though, since we have to use
electron-beam or deep-UV lithograpy to write such small features.
When mass-replicated, the price comes down of course.

regards,

Risto Salmio

Heptagon Oy                          tel/fax: +358 9 4354 2041
Otaniemi Science & Technology Park   e-mail: risto.salmio@xxxxxxxxxxx
Tekniikantie 12                      URL: http://www.heptagon.fi/
FIN-02150 Espoo, FINLAND

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  This sounds like you could get polarizers with
more than 50% transmission since the state of
polarization is changed rather than just absorbing
the unwanted one.

  A 2 minute search of their web site didn't turn
up anything on polarizers though there was a long
list of technical documents.

  Imagine how bright your slide show could be with
(say) 80% transmission pol's in the projector and
80% transmission glasses!  Imagine how much money
it would cost :)

Greg E.

http://angelfire.com/ca/erker



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