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2Physics Quote:
"Many of the molecules found by ROSINA DFMS in the coma of comet 67P are compatible with the idea that comets delivered key molecules for prebiotic chemistry throughout the solar system and in particular to the early Earth increasing drastically the concentration of life-related chemicals by impact on a closed water body. The fact that glycine was most probably formed on dust grains in the presolar stage also makes these molecules somehow universal, which means that what happened in the solar system could probably happen elsewhere in the Universe."
-- Kathrin Altwegg and the ROSINA Team

(Read Full Article: "Glycine, an Amino Acid and Other Prebiotic Molecules in Comet 67P/Churyumov-Gerasimenko"

Wednesday, January 10, 2007

Visible Light Transmitted Through Nanocable

Boston College physicists (L-R) Krzysztof Kempa, Michael Naughton, Jakub Rybczynski and Zhifeng Ren have transmitted visible light through a "nanocoax" cable they developed that is hundreds of times thinner than a human hair [photo courtsey: Boston College]

A team of physicists from Boston College have created the first nanoscale coaxial cables that can transmit visible light. Operating much like the coaxial cables used to distribute television and radio signals, these cables can transmit light with wavelengths nearly 4 times their 200 nm diameter. This discovery defies a key principle that says light cannot pass through a hole much smaller than its wavelength.

Their coaxial cable is based around a carbon nanotube, which forms the central conductor and is surrounded by a concentric ring of transparent aluminium oxide -- which acts as the dielectric layer – and finally a concentric conducting metal ring that acts as the outer conductor. This structure is able to enclose energy and let the cable transmit electromagnetic signals with wavelengths much larger than the diameter of the cable itself.

This achievement is built upon thir earlier (year 2004) invention of a microscopic antenna that captures visible light in much the same way radio antennae capture radio waves. This time they developed a "nanocoax" -- a carbon nanotube-based coaxial cable with a diameter of about 300 nm (a human hair is several hunderd times wider). The nanocoax is designed in a way such that the center wire protruded at one end, forming a light antenna. The other end was blunt, allowing measurement of the light received by the antenna and transmitted through the medium. The researchers were able to transmit both red and green light into the nanocoax and out the other end, indicating that the cable can carry a broad spectrum of visible light.

The researchers claim that the ability to control light over sub-wavelength distances could lead to better optical microscopes, smaller computer chips and more efficient solar panels. It may open the door to a wide array of new technologies, from high-efficiency, inexpensive solar cells to microscopic light-based switching devices for use in optical computing. The technology could even be used to help some blind people see through the creation of artificial retinas.

Reference: "Subwavelength waveguide for visible light",
Appl. Phys. Lett. 90, 021104 (January 8th issue, 2007) Link to Abstract
Authors: J. Rybczynski, K. Kempa, A. Herczynski, Y. Wang, M. J. Naughton, and Z. F. Ren of Dept of Physics, Boston College, MA;
Z. P. Huang and D. Cai of NanoLab Inc., Newton, MA; M. Giersig of Center of Advanced European Studies and Research (CAESAR), Bonn, Germany.

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