Monday, January 18, 2010

Knotty Control Of Light

ד' בשבט תש"ע
Imbolgen 5

In follow-up to the flurry of knotted witch's ladders I've created for WITCHCRAFTS by Liorah Lleucu within the past week or so and my Torah commentary for this past Shabbat (Mind Magic and the Art of Control), this interesting synchronous news article is reported today by Foxnews:

Twisted physics, scientists create knots of light
By Jeanna Bryner - LiveScience

Like your shoelaces or electrical cords, light can get twisted into knots. Now, scientists have used a computer-controlled hologram and theoretical physics to turn a light beam into pretzel-like shapes.

The twisted feat not only led to some pretty cool images, but the results have implications for future laser devices, the researchers say.

"In a light beam, the flow of light through space is similar to water flowing in a river," said lead researcher Mark Dennis of the University of Bristol in England. Even though the light from something like a laser pointer travels in a straight line, it can also flow in whirls and eddies, Dennis explained.

These swirls of light are called optical vortices. Along the vortices the intensity of light reaches zero, or no light.

"The light all around us is filled with these dark lines, even though we can't see them," Dennis said. "Our work actually twists dark filaments within the light beam into knots."

The researchers knew these optical vortices could be created with holograms, which direct the flow of light. By using so-called fibered knot theory, a branch of abstract mathematics inspired by everyday knots, Dennis and his colleagues created customized holograms and reflected a regular laser beam from them.

Each point on the hologram changes the point of the wave's cycle in that part of the light beam. They created a hologram that would change the phase of light so that it flowed around a dark knot.

Their results, detailed online Jan. 17 in the journal Nature Physics, are "firsts" for a couple of reasons. While so-called knot theorists have studied mathematical equations similar to dark knots, the new research created these knots with math functions that followed rules of propagating light. In addition, unlike other dark knots created that have been tangled up with other knots, Dennis and his colleagues produced isolated dark knots within the light beam, he said.

"For me, it shows how physicists can adapt existing pure mathematics, such as knot theory, and find it manifest in physical phenomena," Dennis said. "It also shows how finely we can control the flow and propagation of laser light using holograms. This degree of control is likely to find applications in future laser devices."

Read the entire article at the link above.

The seven knotty witch's ladders I've created recently, from Manifestation to Earth Light:

Earth Light Witch's Ladder - created 1/17
Earth Goddess Witch's Ladder - created 1/17
Sea Faery Witch's Ladder - created 1/16
Witching Hour Witch's Ladder - created 1/15
Dragon Faery Witch's Altar Ladder - created 1/9 - SOLD
Mysteries of the Flame Witch's Ladder - created 1/6 - SOLD
Manifestation Witch's Ladder - created 1/6

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