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Friday, July 21, 2006

Newly developed fiber at MIT can detect light waves.. It sees everything!


     Throw away those cumbersome camera lenses, as MIT has just developed a new and amazing lightweight web fiber that can "see". The new light detecting material, featured in the journal Nature Materials, is expected to have a myriad of uses, from aiding the visually impaired, to outfitting soldiers on the battlefield. And maybe the technology could extend to chic urbane fashions, so you really could have eyes in the back of your head.

The optical system is comprised of mesh-like webs of light-detecting fibers, which can calculate the direction, intensity and characteristic properties of the light wave being detected. MIT researchers consider this latest technology to be an improvement upon traditional optical technologies, such as lenses, filters and detector arrays that are based on the eye and its retina. While the clarity of images sourced from traditional lens technologies is excellent, they do have a number of drawbacks, such as their unidirectional perspective, size, weight, and their susceptibility to damage. By comparison, the optical web is lightweight, flexible, and if shaped as a sphere, the web can detect the entire environment in which it resides.

"When you're looking at something with your eyes, there's a particular direction you're looking in," explains MIT researcher Ayman Abouraddy. "The field of view is defined around that direction. Depending on the lens, you may be able to capture a certain field of view around that direction, but that's it. Until now, most every optical system was limited by an optical axis or direction."

Working in unison at their points of intersection, a spherical array of the 1-millimeter diameter fibers (consisting of a photoconductive glass core encased in a transparent polymer insulator) can pinpoint the exact source of incoming light anywhere along their length. Fink's team has also experimented with flat panel versions of the fibers that when placed in parallel to one another can generate crude computer images of backlit shapes and letters of the alphabet. The computer images are constructed from calculations based on the light intensity distributions detected by the fibers. Researchers suggest that the fibers could be woven into a textile, and a small CPU could provide information about a user's surrounds audibly or on a display screen (Spidey senses tingling!).

The technology could be improved and honed even further if the diameter of the fibers was reduced and the density of the web increased, but the team is more reserved when asked if the web will ever rival the human eye. "Just the idea of imaging with a transparent object is a true eye opener," said team leader, Professor Yoel Fink.

The new optical web system could enhance pre-existing technologies like space telescopes, and lead to a variety of new applications aimed at helping the visually impaired or providing a tactical advantage to soldiers on the battlefield. Researchers say that the transparent web fibers are even capable of interacting with giant computer screens, which could be activated with light beams rather than touch. "It's intriguing - the idea of touching with light. We could use light to enhance interaction with computers and even gaming systems," said Fink.

A web fiber equipped business suit comes highly recommended for those politicians and corporate execs wishing to avoid being stabbed in the back - where "et tu, brut?" becomes "I saw you coming."

Source: Science a Go Go



New Giant Telescope will see 10 times sharper than Hubble's


The 24.5m Giant Magellan Telescope is one of the next generation of large telescopes and will have vision up to 10 times sharper than Hubble's (Illustration: Todd Mason/GMT/Carnegie Observatories)    A giant telescope with a mirror up to 60 metres wide is being planned by the European Southern Observatory. The telescope would be able to detect Earth-like planets around other stars and spot the universe's first galaxies.

The ESO has created a new office to design the European Extremely Large Telescope (E-ELT). "ESO aims to put the E-ELT on a fast track," says Roberto Gilmozzi, the principal investigator for the project.

Project managers have not yet chosen the size of the mirror but say it could range from 30 to 60 metres wide. ESO had previously been considering a 100-metre telescope called the OverWhelmingly Large telescope (OWL). But a review of the concept concluded that the project would be too risky and would take too long to build, Gilmozzi says.

"The advice was to go for a smaller telescope so that there was less risk and so it could be built in a shorter time," he told New Scientist.

International partnerships

Their goal is to build it for €750 million ($950 million) and have it ready to observe by 2015. Gilmozzi says ESO will likely provide about half the funds needed, with more coming from individual ESO member countries. Other funds could come from possible partnerships with non-European countries like the US or Japan, he said.

Two other groups are also pushing forward with plans for giant telescopes. A US-Australian consortium is planning a 24.5-metre instrument called the Giant Magellan Telescope (GMT) to be built by 2016 (see World's largest telescope begins with a spin). And a US-Canadian group is planning the Thirty Meter Telescope (TMT), also to be built by 2016.

The huge mirrors used for these projects will be assembled from smaller segments. "That's way cheaper than trying to build a single big mirror," says TMT team member Ray Carlberg of the University of Toronto, Canada.

The other crucial ingredient is a technology called adaptive optics, which compensates for the way light is blurred by Earth's atmosphere. This involves bouncing light from the telescope off a small corrector mirror, whose shape can change to counteract atmospheric distortion.

New vistas

While space-based telescopes enjoy crystal-clear views, ground-based telescopes have their own advantages. "For a given budget, ground-based telescopes can be much larger than telescopes in space," says GMT project manager Matt Johns of the Carnegie Institution of Washington's Observatories in Pasadena, California, US.

The giant ground-based telescopes will have vision roughly four times sharper than the James Webb Space Telescope (JWST) that will replace Hubble, he says.

That powerful vision should open new vistas for astronomy. "The TMT, along with other telescopes, is largely going to figure out how galaxies form, how stars form and how planets form," says Carlberg.

As supporting technology such as adaptive optics improves, the new telescopes could eventually analyse the gases in the atmospheres of other Earth-like planets.

"Almost everyone is really excited about this planet stuff," Carlberg told New Scientist. "There's a whole vast new area of discovery there."

Source: New Scientist

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