Posted on 01/02/2003 5:19:28 PM PST by sourcery
Combining concepts from electromagnetic radiation research and fiber optics, researchers have created an extreme-ultraviolet, laser-like beam capable of producing tightly-focused light in a region of the electromagnetic spectrum not previously accessible to scientists. Between 10-100 times shorter than visible light waves, the extreme-ultraviolet (EUV) wavelengths will allow researchers to "see" tiny features and carve miniature patterns, with applications in such fields as microscopy, lithography and nanotechnology.
The achievement is based on a new structure called a "waveguide," a hollow glass tube with internal humps that coax light waves into traveling along at the same speed and help the waves reinforce each other.
Reported in the January 2 issue of the journal Nature, the work is part of a continuing project supported by the National Science Foundation (NSF), an independent agency of the U.S. Government that supports science and engineering research and education.
The new beam has peak powers approaching a megawatt and produces nanometer-scale light waves, yet the entire apparatus fits on a moderately sized table.
Expanding upon earlier work, a team of researchers led by Henry Kapteyn and Margaret Murnane of JILA at the University of Colorado create EUV beams by firing a femtosecond laser through the gas-filled waveguide. A femtosecond is one quadrillionth -- 1/1,000,000,000,000,000 -- of a second, and a brief pulse of the laser can be measured in these tiny units. The intense laser light literally rips the gas atoms apart, resulting in charged ions and electrons. The laser beam then accelerates the electrons to very high energies and slams them back into the ions, releasing electromagnetic radiation (in this instance, photons at EUV wavelengths).
Some of the EUV waves can be out of phase with the laser, canceling each other and weakening the strength and coherence of the output beam. However, by creating ripples in the diameter of the waveguide, the Colorado team coaxed the light waves from the laser and EUV beams into traveling at the same speed (a result called "phase matching").
"These waveguide structures are amazingly simple just a modulated, hollow glass tube," said Murnane. "It is as if the laser beam 'surfs' on the modulations and is slowed down just as the speed bumps on the road slow a car down very simply and very effectively," she added.
Slowing down the laser allows it to travel at the same speed as the EUV light and increases the efficiency of the process. The result is a well-synchronized stream of photons firing out of the system -- electromagnetic radiation boosted up to a high-energy, extreme ultraviolet, wavelength.
Unlike some room-sized counterparts, the new, laser-like, EUV source is smaller than any other EUV laser design at these very short wavelengths," said Kapteyn. "The waveguide fiber fits in one hand and the laser fits on a desktop," he added.
Moreover, the peak power of the beam is higher than any other light source at the wavelengths it achieves all the way from the ultraviolet (UV) to the EUV region of the spectrum around 6 nanometers.
The Colorado group hopes to extend the beam's range into what scientists call the "water-window" -- the region of the spectrum below 4 nanometers where the light is perfect for imaging biological structures. Producing a beam in this region would allow the researchers to build a small microscope for imaging living tissues on a desktop or for viewing objects at the nanoscale.
"In 10 years, laser light will span all the way to the x-ray region of the spectrum," speculated Kapteyn. "The light will be used for the most precise microscopes that we can imagine, allowing real-time movies of the complex dance that atoms weave in chemical reactions and in pharmaceuticals yet to be visualized," he added.
The research was principally supported by NSF, with additional funds from the Department of Energy. JILA is managed by both the National Institute of Standards and Technology and the University of Colorado.
### For additional information, please see:
"Laser-Like Beam May Break Barriers to Technological Progress," NSF Release, http://www.nsf.gov/od/lpa/news/02/pr0260.htm
"X-rays light up chemical reactions," PhysicsWeb, July 2001, http://physicsweb.org/article/news/5/7/7
"Powerful Ultrafast Sources get Small," Laser Focus World, August 2001, http://lfw.pennnet.com/Articles/Article_Display.cfm?Section=Articles&Subsection=Display&ARTICLE_ID=113661
A profile of Margaret Murnane is available at: http://www.physicscentral.com/people/people-01-4.html
A profile of Henry Kapteyn is available at: http://jilawww.colorado.edu/~kapteyn/
JILA website: http://jilawww.colorado.edu/
For information on light and the electromagnetic spectrum, please see: http://www.howstuffworks.com/light.htm
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Note: This story has been adapted from a news release issued for journalists and other members of the public. If you wish to quote any part of this story, please credit National Science Foundation as the original source. You may also wish to include the following link in any citation:
http://www.sciencedaily.com/releases/2003/01/030101222126.htm
Sigh.....
Sigh.....
If something first discovered in 1894 qualifies as "new", I wonder how far back we'd have to go before the reporter would describe it as "old".
[This ping list for the evolution -- not creationism -- side of evolution threads, and sometimes for other science topics. To be included, or dropped, let me know via freepmail.]
Fire?
Fuel cells are reported about as "new" technology, even though they were also invented in the mid 1800s. As someone else pointed out, we may have to go back to fire to get them to call it an old technology.
I was apprehensive, that the thread would already be full of the anti-government types whining about this "waste of our tax dollars." The research was NSF funded. Oh the unConstituitional horror. (/sarcasm)
LOL!
I suppose this would help with smaller circuits too, right?
Not likely based on the information here. The key is the phrase "peak power." Since this is a pulsed laser on a femtosecond time scale, it is possible to have enormous peak power but very low average power. How long is the pulse and what is the pulse frequency? One must answer these questions to know how effective it might be as a weapon. I've worked with a "nitrogen laser" pumped tunable dye laser. The pulse durations were on the nanosecond time scale, and peak powers of 100's of kilowatts could be achieved. Average power, however, was in milliwatts, as the laser was "off" most of the time. Very good for doing careful spectroscopy, chemistry, or microscopy, not good for bringing down ICBM's.
Well, maybe they cater to those who might confuse the following text with the image.
beams by firing a femtosecond laser through the gas-filled waveguide.
It is a gas-filled guide of some sort.
Also, you may have a look at these links:
http://www.fibre-optics.hw.ac.uk/Projects/mat16.htm
http://www.el.utwente.nl/tdm/ldg/research/pc_dev/pc_dev.htm
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