Angular Momentum of Light New Tool for Astronomers?

http://sciam.com/article.cfm?chanID=...4F83414B7F0000

"You'd think we'd have figured out light by now. Kids learn about prisms and
lenses in elementary school, people wear Maxwell's equations on T-shirts,
and the quantum version of those equations is the most precise theory in
science. Yet knotted up within the theory is a phenomenon that physicists
are still unraveling: an unexplored property of light.

In addition to color (which depends on the wavelength of the electromagnetic
wave) and polarization (the orientation of the wave), light beams can also
possess orbital angular momentum (the shape of the wave fronts). Optics
researchers discovered this property a decade ago, but for some reason this
realization has failed to propagate much beyond a small community of
specialists [see "Hands of Light," Innovations, Scientific American,
August]. It has barely been noticed even by those with the greatest need to
exploit every conceivable aspect of light--namely, astronomers."...

Klaatu wrote:

http://sciam.com/article.cfm?chanID=...4F83414B7F0000

"You'd think we'd have figured out light by now. Kids learn about prisms and
lenses in elementary school, people wear Maxwell's equations on T-shirts,
and the quantum version of those equations is the most precise theory in
science. Yet knotted up within the theory is a phenomenon that physicists
are still unraveling: an unexplored property of light.

In addition to color (which depends on the wavelength of the electromagnetic
wave) and polarization (the orientation of the wave), light beams can also
possess orbital angular momentum (the shape of the wave fronts). Optics
researchers discovered this property a decade ago, but for some reason this
realization has failed to propagate much beyond a small community of
specialists [see "Hands of Light," Innovations, Scientific American,
August]. It has barely been noticed even by those with the greatest need to
exploit every conceivable aspect of light--namely, astronomers."...

Posted by Uncle Al in news:sci.physics

A photon's magnetic and electric fields are strictly AC. They
oscillate. There is nothing "frozen" about them.

Circular and elliptical polarization. Get an optics book or Google.
Linear polarized light is a superposition of equal amounts of left-
and right- circularly polarized light. Then you can look up optical
rotatory dispersion and circular dichroism spectroscopies re the
Kramers-Kronig relationship.

Transferring angular momentum to a target by irradiating it with
circularly polarized light is old hat.