Glenn
2012-12-01 09:06:29 UTC
Dette må da være nogle radioamatør eksperimenter værdigt:
Ved hjælp af f.eks. 1000 fasede radioantenner kan du lave afbøjende
radiokegler, der kan gå bagom forhindringer - og sikkert også modtage
bagom forhindringer - f.eks. månen eller et højt bjerg. Ydermere spredes
radiokeglen ikke. Kan nogen forklare ud af artiklen hvorfor?
Ved modtagelse burde de muliggør at radioteleskoper kan nå endnu længere
ud - f.eks. bagom Mælkevejens centrum?
LoS (Line-of-Sight) krav for optimal radioforbindelse er ikke nødvendig
for f.eks. mikrobølger - og muligvis kan langt mindre sendeeffekt benyttes:
Nov 30, 2012, Light bends itself round corners:
http://physicsworld.com/cws/article/news/2012/nov/30/light-bends-itself-round-corners
Citat: "...
Five years ago physicists showed that certain kinds of laser beam can
follow curved trajectories in free space.
...
The concept of self-bending light was inspired by quantum mechanics and
the realization in 1979 by Michael Berry and Nandor Balazs that the
Schrödinger equation could support "Airy" wavepackets of particles,
which accelerate without an external force.
...
To do this they passed a centimetre-wide ordinary laser beam through a
device known as a spatial light modulator that adjusted the phase of the
beam at thousands of points across its width.
...
their interference produced a region of maximum intensity that curved
sideways in the shape of a gentle parabola across the beam as it
propagated forward, along with a number of fainter regions on one side.
...
other intriguing characteristics. One is that it is non-diffracting
...
The other unusual property is that of self-healing. This means that if
part of the beam is blocked by opaque objects, then any disruptions to
the beam's intensity pattern could gradually recover as the beam travels
forward.
A limitation of the Florida work, however, is that Airy beams can only
be bent through relatively small angles up to about 15 degrees.
...
A month later, two teams produced such beams in the lab – each bending
light a 60-degree arc.
..."
Glenn/OZ1HFT
Ved hjælp af f.eks. 1000 fasede radioantenner kan du lave afbøjende
radiokegler, der kan gå bagom forhindringer - og sikkert også modtage
bagom forhindringer - f.eks. månen eller et højt bjerg. Ydermere spredes
radiokeglen ikke. Kan nogen forklare ud af artiklen hvorfor?
Ved modtagelse burde de muliggør at radioteleskoper kan nå endnu længere
ud - f.eks. bagom Mælkevejens centrum?
LoS (Line-of-Sight) krav for optimal radioforbindelse er ikke nødvendig
for f.eks. mikrobølger - og muligvis kan langt mindre sendeeffekt benyttes:
Nov 30, 2012, Light bends itself round corners:
http://physicsworld.com/cws/article/news/2012/nov/30/light-bends-itself-round-corners
Citat: "...
Five years ago physicists showed that certain kinds of laser beam can
follow curved trajectories in free space.
...
The concept of self-bending light was inspired by quantum mechanics and
the realization in 1979 by Michael Berry and Nandor Balazs that the
Schrödinger equation could support "Airy" wavepackets of particles,
which accelerate without an external force.
...
To do this they passed a centimetre-wide ordinary laser beam through a
device known as a spatial light modulator that adjusted the phase of the
beam at thousands of points across its width.
...
their interference produced a region of maximum intensity that curved
sideways in the shape of a gentle parabola across the beam as it
propagated forward, along with a number of fainter regions on one side.
...
other intriguing characteristics. One is that it is non-diffracting
...
The other unusual property is that of self-healing. This means that if
part of the beam is blocked by opaque objects, then any disruptions to
the beam's intensity pattern could gradually recover as the beam travels
forward.
A limitation of the Florida work, however, is that Airy beams can only
be bent through relatively small angles up to about 15 degrees.
...
A month later, two teams produced such beams in the lab – each bending
light a 60-degree arc.
..."
Glenn/OZ1HFT