To make a better optical fiber for transmitting laser beams, the first idea that comes to mind is probably not a nice long hydrogen bath.
And yet, scientists have known for years that hydrogen can alter the performance of optical fibers, which are often used to transmit or even generate laser light in optical devices. Researchers at the National Institute of Standards and Technology (NIST) have put this hydrogen "cure" to practical use, making optical fibers that transmit stable, high-power ultraviolet laser light for hundreds of hours.
This is a micrograph of an optical fiber that has been infused with hydrogen and cured with ultraviolet light (here shown transmitting violet laser light.) Fibers treated this way can transmit stable, high-power ultraviolet laser light for long periods of time, resisting the damage usually caused by UV light. The diameter of the pattern of air holes surrounding the core is 62.5 micrometers.
NIST scientists expect these hydrogen-treated fibers, described in Optics Express,* to reduce errors in logic operations in their quantum computing experiments.
Optical fibers generally are not able to transmit ultraviolet light because the short wavelength light can interact with dopants or impurities in the fibers, resulting in so-called "solarization" damage and extreme losses of beam intensity. The fibers effectively shut down. Hydrogen molecules have been shown to heal this damage as it occurs.
NIST researchers tested two types of fibers with solid cores made of fused silica surrounded by lattices of air holes, which form a crystal structure that maintains the shape of transmitted laser beams. The fibers were infused with hydrogen gas at 100 times standard atmospheric pressure for four to six days.
Conveniently, some of the fibers could be treated in NIST's hydrogen pipeline materials testing facility.** After the hydrogen diffused into the fiber cores, the fibers were cured by exposure to ultraviolet laser light for several days.
NIST researchers then tested the fibers by transmitting ultraviolet laser light through them. The fibers did not display any solarization damage, even at output powers as high as 125 milliwatts (mW) at 313 nanometer (nm) laser wavelengths—several times the beam intensity needed for the group's quantum computing experiments. The combination of hydrogen infusion and curing with ultraviolet light "appears to confer long-term resistance" to this type of damage, according to the paper. The fibers also lose very little of the laser light as it is transmitted.
For comparison, NIST researchers also tested fibers that were not treated with hydrogen. With 313 nm wavelength laser light at 100 mW power, light transmission through the fibers dropped to zero in four hours, confirming the value of the hydrogen treatment.
The treated fibers could be used to transmit a wide range of infrared, visible and ultraviolet wavelengths of light, according to the research team. When used at NIST to transmit laser light to trap ions (electrically charged atoms), the fibers reduce stray light and fluctuations in laser beam pointing and make it possible to transfer ultraviolet light between separate optical tables, the paper notes. The fibers also can help "clean up" misshapen beams, the researchers say.
The same NIST research group has achieved many "firsts" using trapped ions to demonstrate building blocks for quantum computers, which would use the exotic properties of the quantum world to solve problems considered intractable today.
* Y. Colombe, D.H. Slichter, A.C. Wilson, D.G. Leibfried and D.J. Wineland. Single-mode optical fiber for high-power, low-loss UV transmission. Optics Express, Vol. 22, Issue 16, pp. 19783-19793. Published online Aug. 8, 2014. DOI:10.1364/OE.22.019783.
** See 2010 NIST Tech Beat article, "Future of Hydrogen Fuel Flows Through New NIST Test Facility," at http://www.nist.gov/public_affairs/tech-beat/tb20100216.cfm#hydrogen.
Laura Ost | Eurek Alert!
Tiny Drops of Early Universe 'Perfect' Fluid
02.09.2015 | Brookhaven National Laboratory
02.09.2015 | European Southern Observatory ESO
China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from University of Arizona geoscientists. The study is the first to explain how the steep-fronted plateau formed.
China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from...
The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets still stick to them. Now, Penn State researchers have developed nano/micro-textured, highly slippery surfaces able to outperform these naturally inspired coatings, particularly when the water is a vapor or tiny droplets.
Enhancing the mobility of liquid droplets on rough surfaces could improve condensation heat transfer for power-plant heat exchangers, create more efficient...
Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.
"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...
A University of Oklahoma astrophysicist and his Chinese collaborator have found two supermassive black holes in Markarian 231, the nearest quasar to Earth, using observations from NASA's Hubble Space Telescope.
The discovery of two supermassive black holes--one larger one and a second, smaller one--are evidence of a binary black hole and suggests that supermassive...
A team of European researchers have developed a model to simulate the impact of tsunamis generated by earthquakes and applied it to the Eastern Mediterranean. The results show how tsunami waves could hit and inundate coastal areas in southern Italy and Greece. The study is published today (27 August) in Ocean Science, an open access journal of the European Geosciences Union (EGU).
Though not as frequent as in the Pacific and Indian oceans, tsunamis also occur in the Mediterranean, mainly due to earthquakes generated when the African...
20.08.2015 | Event News
20.08.2015 | Event News
19.08.2015 | Event News
02.09.2015 | Physics and Astronomy
02.09.2015 | Life Sciences
02.09.2015 | Awards Funding