A Space & astronomy forum. SpaceBanter.com

Go Back   Home » SpaceBanter.com forum » Space Science » News
Site Map Home Authors List Search Today's Posts Mark Forums Read Web Partners

MIT light detector may speed up interplanetary communications(Forwarded)



 
 
Thread Tools Display Modes
  #1  
Old March 24th 06, 01:03 AM posted to sci.space.news
external usenet poster
 
Posts: n/a
Default MIT light detector may speed up interplanetary communications(Forwarded)

News Office
Massachusetts Institute of Technology
Cambridge, Massachusetts

March 20, 2006

MIT light detector may speed up interplanetary communications

MIT researchers have developed a tiny light detector that may allow for
super-fast broadband communications over interplanetary distances.
Currently, even still images from other planets are difficult to retrieve.

"It can take hours with the existing wireless radio frequency technology
to get useful scientific information back from Mars to Earth. But an
optical link can do that thousands of times faster," said Karl Berggren,
assistant professor in the Department of Electrical Engineering and
Computer Science (EECS).

Berggren, who is also affiliated with the Research Laboratory of
Electronics (RLE), developed the detector with colleagues from the RLE,
Lincoln Laboratory and Moscow State Pedagogical University.

The new detector improves the detection efficiency for single photos to 57
percent at a wavelength of 1,550 nanometers (billionths of a meter), the
same wavelength used by optical fibers that carry broadband signals to
offices and homes today. That's nearly three times the current detector
efficiency of 20 percent.

The result will be real-time collection of large amounts of data from
space. The work may ultimately permit the transmission of color video
between astronauts or equipment in outer space and scientists on Earth.

The detector, which uses nanowires and superconductor technology, can
sense extremely low light or laser signals in the infrared part of the
optical spectrum -- down to a single photon, the smallest and most basic
unit of light. That has not been possible using conventional optical
systems.

The detector also could be applied to quantum cryptography and biomedical
imaging, but the most immediate application is probably interplanetary
communication, Berggren said.

Because of the vast distances between planets, current optical systems
would require a large laser and a lot of power to send data at a high
rate. And this would have to be done on spacecraft, which are typically
starved for power. So there is a need for devices like the new detector
that can operate quickly and, because they are more sensitive, receive
signals from smaller lasers that do not use much power, Berggren said.

Single-photon detectors have been made by MIT and other researchers in the
past, but they have not been both speedy and efficient at detecting light.
The way Berggren and his colleagues improved the efficiency was to add a
"photon trap" to the detector as well as an anti-reflection coating to
keep light from bouncing off its surface.

The photon trap is an optical cavity consisting of the nanowire detector,
a carefully measured gap of glass and a mirror. The nanowire is coiled
tightly like the metal on the back of a refrigerator to broaden its area
of overlap with the laser light.

The wire is then cooled to just above absolute zero. That temperature is
the point at which it becomes a superconductor and at which it can detect
the absorbed photons. If a photon is not absorbed the first time it
touches the wire, it bounces back and forth between the coiled nanowire
and the mirror so it has more opportunities to be absorbed. The more
photons that are absorbed, the greater the efficiency of the detector.

Berggren and his colleagues published their discovery in the January 23
issue of Optics Express. His co-authors are MIT RLE post-doctoral
researcher Kristine Rosfjord and RLE/EECS graduate students Joel Yang,
Vikas Anant and Eric Dauler; Lincoln Laboratory staff member Andrew
Kerman; and Boris Voronov and Gregory Gol'tsman of Moscow State
Pedagogical University.

The researchers are now working to make the detector even more efficient.

This work was funded in part by the U.S. Air Force.

IMAGE CAPTIONS:

[Image 1:
http://web.mit.edu/newsoffice/2006/n...1-enlarged.jpg (44KB)]
MIT Assistant Professor Karl Berggren of electrical engineering and
computer science works on nanowires in the lab. Photo: Donna Coveney

[Image 2:
http://web.mit.edu/newsoffice/2006/n...2-enlarged.jpg (42KB)]
Assistant Professor Karl Berggren used the machine behind him to make
nanowires, new technology that may speed interplanetary communications.
Photo: Donna Coveney


 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
New Physics Based on Yoon's Universal Atomic Model newedana Astronomy Misc 236 May 2nd 06 09:25 AM
How can Orbital Electron Rotate Permanently without Energy Supply? newedana Astronomy Misc 217 December 8th 05 07:36 PM
Can't get out of the universe "My crew will blow it up"!!!!!!!!!!! zetasum History 0 February 5th 05 12:06 AM
Mind-2, Time waves and Theory of Everything Yoda Misc 0 April 20th 04 06:11 AM
UFO Activities from Biblical Times (Long Text) Kazmer Ujvarosy UK Astronomy 3 December 25th 03 11:41 PM


All times are GMT +1. The time now is 05:56 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 SpaceBanter.com.
The comments are property of their posters.