NIST Tech Beat - April 27, 2006

Physicists at the National Institute of Standards and Technology (NIST) have used lasers to cool and trap erbium atoms, a “rare earth” heavy metal with unusual optical, electronic and magnetic properties. The element has such a complex energy structure that it was previously considered too wild to trap. The demonstration, reported in the April 14 issue of Physical Review Letters,* might lead to the development of novel nanoscale devices for telecommunications, quantum computing or fine-tuning the properties of semiconductors.

Laser cooling and trapping involves hitting atoms with laser beams of just the right color and configuration to cause the atoms to absorb and emit light in a way that leads to controlled loss of momentum and heat, ultimately producing a stable, nearly motionless state. Until now, the process has been possible only with atoms that switch easily between two energy levels without any possible stops in between. Erbium has over 110 energy levels between the two used in laser cooling, and thus has many ways to get “lost” in the process. NIST researchers discovered that these lost atoms actually get recycled, so trapping is possible after all.

The NIST team heated erbium to over 1300 degrees C to make a stream of atoms. Magnetic fields and six counter-propagating purple laser beams were then used to cool and trap over a million atoms in a space about 100 micrometers in diameter. As the atoms spend time in the trap, they fall into one or more of the 110 energy levels, stop responding to the lasers, and begin to diffuse out of the trap. Recycling occurs, though, because the atoms are sufficiently magnetic to be held in the vicinity by the trap’s magnetic field. Eventually, many of the lurking atoms fall back to the lowest energy level that resonates with the laser light and are recaptured in the trap.

The erbium atoms can be trapped at a density that is high enough to be a good starting point for making a Bose-Einstein condensate, an unusual, very uniform state of matter used in NIST research on quantum computing. Cold trapped erbium also might be useful for producing single photons, the smallest particles of light, at wavelengths used in telecommunications. In addition, trapped erbium atoms might be used for “doping” semiconductors with small amounts of impurities to tailor their properties. Erbium—which, like other rare earth metals, retains its unique optical characteristics even when mixed with other materials—is already used in lasers, amplifiers and glazes for glasses and ceramics. Erbium salts, for example, emit pastel pink light.

* J.J. McClelland and J.L. Hanssen. 2006. Laser cooling without repumping: a magneto-optical trap for erbium atoms. Physical Review Letters. April 14.

In a ceremony April 19 in Washington, D.C., Vice President Dick Cheney and Commerce Secretary Carlos Gutierrez presented six U.S. organizations with the Malcolm Baldrige National Quality Award, the nation’s highest honor for performance excellence and quality achievement.

“With innovative practices, a strong commitment to excellence and visionary leadership, the 2005 Baldrige Award recipients represent the best of American business, education and health care,” said Commerce Secretary Gutierrez. He added, “Since 1988, the Malcolm Baldrige National Quality Award program has gained world-wide recognition for the vital role it is playing in helping organizations achieve and sustain excellence.”

The 2005 Baldrige Award recipients are: Sunny Fresh Foods, Inc., Monticello, Minn. (manufacturing); DynMcDermott Petroleum Operations, New Orleans, La. (service); Park Place Lexus, Plano, Texas (small business); Richland College, Dallas, Texas (education); Jenks Public Schools, Jenks, Okla. (education); and Bronson Methodist Hospital, Kalamazoo, Mich. (health care).

This is the first time that a community college, an automotive dealership and an oil industry business have received a Baldrige Award. Sunny Fresh Foods is a two-time Baldrige Award recipient; it received the award in the small business category in 1999. Baldrige Award recipients can reapply after five years.

Following a six-month evaluation process, including an on-site visit by a team of examiners, the 2005 Baldrige Award recipients were selected from among 64 applicants. An independent board of examiners evaluated them in seven areas: leadership; strategic planning; customer and market focus; measurement, analysis and knowledge management; human resource focus; process management; and results.

The Malcolm Baldrige National Quality Award, managed by the Commerce Department’s National Institute of Standards and Technology (NIST) in conjunction with the private sector, promotes organizational quality, recognizes performance excellence achievements of U.S. organizations and publicizes these organizations’ successful performance strategies.

For further information see: http://www.nist.gov/public_affairs/releases/baldrige_ceremony05.htm.

Media Contact:
Jan Kosko, kosko@nist.gov, (301) 975-2767

3D Image Data of Slotted Disk from two different systems

The two sets of images above show data obtained from two instruments used to measure a slotted disk. The top set shows less noisy or more precise data.

Credit: NIST

View a high-resolution version of this image.

Three-dimensional imaging devices are becoming important measuring tools in the manufacturing, construction and transportation sectors. Numerous models of the imaging devices, capable of digitally capturing the existing conditions of objects from as small as pipe fittings to as large as an entire bridge, are on the market. A lack of standard tests to verify manufacturers' performance specifications is inhibiting wider market acceptance of these devices.

In response, researchers at the National Institute of Standards and Technology (NIST) recently established an indoor, artifact-based facility to create new test protocols and performance measures to evaluate such 3D imaging systems. Several prototype artifacts (e.g., spheres, a stairway, and a slotted-disc) are currently being tested for evaluating both instruments and software.

NIST researchers reported on progress in establishing the new facility at a recent conference.* The new facility is part of a larger effort to provide standard test protocols and associated facilities for evaluating and calibrating these instruments. In addition to the indoor, artifact-based facility, NIST also operates an indoor 60 meter (m) range calibration facility and is developing a separate 3D facility so that manufacturers or research groups can send in instruments for spatial calibrations. Finally, NIST will establish an outdoor ranging facility for evaluating the performance of 3D imaging systems up to 150 m to 200 m.

This summer a consensus-based standards development process will begin. Protocols for evaluating the range performance of imaging devices as well as a draft list of commonly used terminology developed during a series of workshops held at NIST, will be submitted to ASTM International, a standards-development organization.

These standards will provide objective, repeatable comparisons of different 3-D imaging devices, reduce confusion about terminology and increase user confidence in the systems, according to Alan Lytle, leader of the NIST Construction Metrology and Automation Group.

* G.S. Cheok, A M. Lytle and K.S. Saidi. Status of the NIST 3D imaging system performance evaluation facility. April 17-21 2006. SPIE Defense and Security Symposium. Paper 6214-17. For further information about the 60 m calibration range, contact Steven Phillips (steven.phillips@nist.gov).

Media Contact:
John Blair, john.blair@nist.gov, (301) 975-4261

Measurements May Help Show If Constants Are Changing

Physicists at JILA have performed the first-ever precision measurements using ultracold molecules, in work that may help solve a long-standing scientific mystery—whether so-called constants of nature have changed since the dawn of the universe.

The research, reported in the April 14 issue of Physical Review Letters,* involved measuring two phenomena simultaneously—electron motion, and rotating and vibrating nuclei—in highly reactive molecules containing one oxygen atom and one hydrogen atom. The researchers greatly improved the precision of these microwave frequency measurements by using electric fields to slow down the molecules, providing more time for interaction and analysis. JILA is a joint institute of the National Institute of Standards and Technology (NIST) and the University of Colorado at Boulder.

Compared to the previous record, set more than 30 years ago, the JILA team improved the precision of one frequency measurement 25-fold and another 10-fold. This was achieved by producing pulses of cold molecules at various speeds, hitting each group with a microwave pulse of a selected frequency, and then measuring how many molecules were in particular energy states. The apparatus and approach were similar to those used in the NIST-F1 cesium atomic fountain clock, the nation’s primary time standard, raising the possibility of designing a clock that keeps time with molecules, instead of atoms.

The JILA team’s ability to make two molecular measurements at once enables scientists to apply mathematical calculations to probe the evolution over time of fundamental natural properties such as the fine structure constant, which is widely used in research to represent the strength of electromagnetic interactions. Another research group at the National Radio Astronomy Observatory plans to make similar frequency measurements soon of the same molecules produced in distant galaxies, which are so far from Earth that they represent a window into ancient history. By comparing precision values for the fine structure constant on Earth and in distant parts of the universe, scientists hope to determine whether this constant has changed over 10 billion years. Because the fine structure constant is used in so many fields of physics, these measurements are a way to test the consistency of existing theories. The JILA measurements could enable any change in the fine structure constant over time to be determined with a precision of one part per million.

The work at JILA is supported by the National Science Foundation, NIST, the Department of Energy, and the Keck Foundation.

*E.R. Hudson, H.J. Lewandowski, B.C. Sawyer, and J.Ye. 2006. Cold molecule spectroscopy for constraining the evolution of the fine structure constant. Physical Review Letters. April 14 (Vol. 96, 143004).

Machines can respond to simple electronic commands such as “stop,” “start” and “grind,” but they are not very good at figuring out complex orders or unstated common sense. Command a machine to “paint the computer case before you box it,” or “provide power to the computer before you switch it on” and it is very possible the machine will box the product before the case is dry, or plug and then unplug a computer before switching it on. The meaning of the word “before” is quite different in these two cases. Ontologists, researchers who make it their business to understand the thought process, hope to end the age of stupid machines.

Last month, ontologists who have created some of the most advanced logic systems, agreed at a National Institute of Standards and Technology (NIST) workshop to share their leading-edge concepts on such comprehensive ideas as time, space and process. The promise to cooperate, expressed in a 10-item communiqué* issued at the end of the two-day workshop, eventually could lead to software programs that will equip machines with mutually compatible frames of reference, enabling them to interpret and act on commands with near human common sense.

Efforts to equip machines with artificial intelligence capacity have, up to now, been relatively rudimentary. Software programs might, for instance, give machines used to make furniture considerable “understanding” of terms and frames of reference used in the furniture business. But such collected knowledge known as a “lower ontology” is of limited use, and human operation is necessary at virtually every step in the manufacturing process. A machine empowered by programs that incorporate expanded frames of reference of such “higher ontologies” as space and cost might be able to begin making design and shipping decisions virtually on its own.

“We believe we have planted an historic stake in the ground by enabling the leading upper ontologists throughout the world to come together and sign this agreement to cooperate,” says Steven Ray, chief of NIST’s Manufacturing Systems Integration Division and coordinator of the Upper Ontology Summit at NIST. The ontologists will use the Internet and future meetings to exchange information on their systems. A second Upper Ontology Summit may be scheduled as part of next year’s NIST Interoperability Week events.