Rainbow trapping in light pulses

Jul 14, 2010

Over the past decade, scientists have succeeded in slowing pulses of light down to zero speed by letting separate frequency components of the pulse conspire in such a way that a receptive medium through which the pulse is passing can host the information stored in the pulse but not actually absorb the pulse's energy. Trapping light means either stopping the light temporally or confining the light in space. Scientists have also been able to trap a light pulse in a tiny enclosure bounded by metamaterials; the light pulse retains its form but is kept from moving away.

Previously only light of a short frequency interval could be trapped in this way. Now a group of scientists at Nanjing University in China have shown how a rather wide spectrum of light -- a rainbow of radiation -- can be trapped in a single structure.

They propose to do this by sending the light rays into a self-similar-structured dielectric waveguide (SDW) -- essentially a light pipe with a cladding of many layers.

Light of different colors propagates separately in (or is contained within) different layers, the layers each being tailored by color. They replace the conventional periodically-spaced, identical cladding layers with a non-periodic, self-similar pattern of successive layers made from two materials, A and B, with slightly different thicknesses and indices of refraction.

Self similarity, in this case, means that the pattern of layers successively outwards would be as follows: A, AB, ABBA, ABBABAAB, and so forth.

"The effect might be applied for on-chip spectroscopy or on-chip 'color-sorters,'" says Ruwen Peng, one of the Nanjing researchers. "It might also be used for photon processing and information transport in optical communications and ." Peng and her associates, who published their results in the American Institute of Physics' journal , expect that they can create trapped "rainbows" for light in many portions of the , including microwave, terahertz, infrared, and even visible.

Explore further: New insights found in black hole collisions

More information: The article "'Rainbow' trapped in a self-similar coaxial optical waveguide" by Qing Hu, Jin-Zhu Zhao, Ru-Wen Peng, Feng Gao, Rui-Li Zhang, and Mu Wang was published online in the journal Applied Physics Letters in April, 2010. See: link.aip.org/link/APPLAB/v96/i16/p161101/s1

Provided by American Institute of Physics

4.3 /5 (8 votes)
add to favorites email to friend print save as pdf

Related Stories

Scientists create artificial mini 'black hole'

Jun 03, 2010

(PhysOrg.com) -- Scientists from China have built a device that can trap and absorb microwaves coming from all directions with a 99% absorption rate - a property that makes the device simulate, to some extent, ...

Radio pulses from pulsar appear to move faster than light

Jan 14, 2010

(PhysOrg.com) -- Laboratory experiments in the last few decades have shown that some things can appear to move faster than light without contradicting Einstein's special theory of relativity, but now astrophysicists ...

Researchers develop ultrafast oscilloscope on a chip

Nov 06, 2008

(PhysOrg.com) -- As photonics -- using beams of light in place of electricity for communications and computing -- becomes more common, engineers need new tools for troubleshooting. Now researchers at Cornell ...

Recommended for you

New insights found in black hole collisions

Mar 27, 2015

New research provides revelations about the most energetic event in the universe—the merging of two spinning, orbiting black holes into a much larger black hole.

X-rays probe LHC for cause of short circuit

Mar 27, 2015

The LHC has now transitioned from powering tests to the machine checkout phase. This phase involves the full-scale tests of all systems in preparation for beam. Early last Saturday morning, during the ramp-down, ...

Swimming algae offer insights into living fluid dynamics

Mar 27, 2015

None of us would be alive if sperm cells didn't know how to swim, or if the cilia in our lungs couldn't prevent fluid buildup. But we know very little about the dynamics of so-called "living fluids," those ...

Fluctuation X-ray scattering

Mar 26, 2015

In biology, materials science and the energy sciences, structural information provides important insights into the understanding of matter. The link between a structure and its properties can suggest new ...

Hydrodynamics approaches to granular matter

Mar 26, 2015

Sand, rocks, grains, salt or sugar are what physicists call granular media. A better understanding of granular media is important - particularly when mixed with water and air, as it forms the foundations of houses and off-shore ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.