No one's sure yet where atom optics will lead -- but the possibilities
border on the fantastic.

Most of us think of optics as using matter (in the form of mirrors and lenses) to direct and manipulate light. Atom optics reverses the roles of matter and light -- it uses laser light to direct and manipulate beams of atoms, or "matter waves."

When in 1993 Pierre Meystre and his colleagues at the University of Arizona predicted that it is possible to combine beams of atoms just as beams of laser light are mixed to form a new laser light beam, "it sounded crazy," he admitted.

Then in March 1999, Nobel Prize winner William D. Phillips and his group at the Commerce Department's National Institute of Standards and Technology (NIST) proved in experiments how it can be done.

They coaxed ultra cold atoms into three separate waves analogous to laser-like light, then combined them to create a new, fourth wave. This proved that "nonlinear" systems -- systems in which output is not proportional to input -- apply in atom optics.

"Suddenly, everything we predicted worked, which was amazing," Meystre said. "Funding for research on ultra cold atoms -- which is what this is all about -- is just exploding."

Meystre is Chair of Quantum Optics at the Optical Sciences Center, and professor of optical sciences and professor of physics at UA. His forthcoming book, "Atom Optics" (Springer Verlag, 2001), will be the first one published on that subject.

Louis-Victor, Prince de Broglie, first postulated the concept of atoms as waves in 1924. Just as light behaves both as waves or particles (photons), de Broglie posited, so matter must behave as particles (atoms) or waves (matter waves, or de Broglie waves).

For that work, de Broglie won the Nobel Prize in Physics in 1929.

This particle/wave duality may be one of the most unsettling aspects of quantum mechanics, Meystre said in a lecture he gave in Germany as an Alexander von Humboldt Prize winner in 1997.

Only in the past decade have scientists been able to study the wave properties of whole atoms in any detail. That's because atoms must be chilled to almost absolute zero (zero Kelvin), where they are slowed almost to a dead stop, before they clearly exhibit their wave-like nature.

In the past five years, scientists have discovered how to cool atoms to one millionth of a degree Kelvin using laser light. That's about one billion times colder than room temperature -- and one million times colder than interstellar space, Meystre noted.

"At these extreme temperatures, the world is an utterly strange place where our everyday common sense is useless, quantum physics rules with its counterintuitive laws, and atoms behave as waves," he said. "At these temperatures, the wavelength of atoms becomes as long or longer than visible light wavelengths."

Scientists already have demonstrated basic atom optical elements such as atomic mirrors, atomic beam splitters and atomic gratings. They also have developed crude atom lasers, devices that pulse individual atoms into a coherent beam of atoms in a single quantum state. (All atoms in a single quantum state execute the same motion.)

More practical atom lasers could lead to applications in precision nanofabrication, atom holography and "undreamed of applications that will come as surprises," Meystre predicts.

"We have this vision for atom optics, which is integrated atom optics -- atom optics on a chip," he said. "One problem with current atom optics experiments is that they are really quite big. They take up a couple of tables in the laboratory. The big push is to do atom optics on the cheap, as electronics is done on the cheap," by guiding atoms with magnetic and electrical fields in something the size of an electronic chip.

Atom holography is another stunning idea. Instead of making an image in light as is done in conventional holography, atom optics would make the hologram of atoms.

"What this means is, we could make a real, 3-dimensional replica of some object. We could copy objects," Meystre said.

"All of the individual steps to do this with nonlinear atom optics have been demonstrated. It's just a matter of making it work all together. I think it will happen in the next two or three years."

Quantum computing, quantum cryptography and atom lithography are other possible technologies that depend on reaching a deeper theoretical understanding of the fundamental physics that governs how ultra cold atoms behave.

This kind of fundamental physics is Meystre's research forte.

The Army, the Office of Naval Research, the National Science Foundation and, most recently, NASA have awarded Meystre and his colleagues hundreds of thousands of dollars in new research money in the past year.

The most major new grant, from the Department of Defense, established a 5-year, $5 million research consortium of Harvard, MIT, Stanford, UA and Yale to develop novel high technology sensing devices that will make current state-of-the-art sensors used for strategic navigation, guidance, detection and mapping obsolete.

Meystre and UA optical sciences Professor Ewan Wright collaborate in the consortium with other leading U.S. scientists who are pioneering atom optics, including Stanford's Steven Chu, who won a 1997 Nobel Prize for developing techniques to cool and trap atoms with laser light.

Future "matter wave sensors" could include a new class of compact atom-laser gyroscopes at least a million times more sensitive than current laser gyroscopes and ultra-sensitive gravity-measuring sensors for detecting underground tunnels and chambers or undiscovered oil and mineral deposits.

In his newest research project, funded by the NASA Office of Biological and Physical Research, Meystre will study how atom optics would work in the microgravity of space.

The ultracold atoms used in atom optics are so slow-moving that gravity pulls them to Earth. Magnetism can be used to keep beams of atoms from falling down, Meystre said, but magnetism and electrical fields change the properties of the atoms and degrade the "coherence," or the "cleanness" of atom beams.

Atom holography and atom lithography for nanoscale manufacturing (smaller than a billionth of a meter) and inertial sensors that would be billions of times more sensitive than counterpart optical devices for navigation, tracking and guidance are examples of atom optics applications that would best be done in microgravity.

Related websites:

UA Chair of Quantum Optics page

Laboratories for Research in Quantum Optics

Optical Sciences Center


[Contact: Pierre Meystre, Lori Stiles]

15-Feb-2001