On Tue, 13 Sep 2011 17:52:35 -0700, Richard Clark
wrote:

On Tue, 13 Sep 2011 13:40:37 -0400, "J.B. Wood"
wrote:

(I hope this doesn't turn out to be another CFA-like pursuit).

I've been hearing presentations of this stuff for 7 or 10 years now -
optical tweezers.

The "vorticity" can be seen in the graphic headed "Figures at a
glance":
http://www.nature.com/nphoton/journa...TON-201106#/f1

This is not to speculate about applications in the HF where energies
are many, many decades down from visible light. Where light is
tweezing molecules (very small ones), HF would be vastly
imperceptible. It would seem this reference, then, is gratuitous - a
form of authority inflation.

There are curious contradictions found:
"This novel radio technique allows the implementation of, at least in
principle, an infinite number of channels on one and the same
frequency, even without using polarization or dense coding
techniques."
compared with:
"Already with this setup one can obtain four physically distinct
channels on the same frequency by additionally introducing the use of
polarization, in this case independent from OAM. A further
multiplication of a factor five after the implementation of
multiplexing, yields a total of 20 channels in the same frequency."

Soooo. A special vorticity technique that does not use polarization
(even though they describe it as such) and does not use coding, can
demonstrate novel outcomes when paired with polarization and coding
(for which the outcome is fairly well established).

Why isn't this peer reviewed in EM proceedings?

73's
Richard Clark, KB7QHC

Any strong laser beam will trap dust particles and pull them towards
a direction, I do not remember was it towards the light source or away
from it.
I consider that a thermal effect.

The effect is stunning when you see it the first time.
I worked as helper guy for laser shows, and we used Argon lasers
up to 30 watt output. Suddenly some bright spots aligned at the
beam and slowly moved along it. Dust particles in the air,
of a certain size.

w.