atom optics

atom optics [¦ad·əm ′äp·tiks]

(physics)

The use of laser light and nanofabricated structures to manipulate the motion of atoms in the same manner that rudimentary optical elements control light.

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Atom optics

The use of laser light and nanofabricated structures to manipulate the motion of atoms in the same manner that rudimentary optical elements control light. The term refers to both an outlook in which atoms in atomic beams are thought of and manipulated like photons in light beams, and a collection of demonstrated techniques for doing such manipulation. Two types of atom optics elements have existed for some time: slits and holes used to collimate molecular beams (the analog of the pinhole camera), and focusing lenses for atoms and molecules (for example, hexapole magnets and quadrupole electrostatic lenses). However, in the 1980s the collection of optical elements for atoms expanded dramatically because of the use of near-resonant laser light and fabricated structures to make several types of mirrors as well as diffraction gratings. The diffraction gratings are particularly interesting because they exploit and demonstrate the (de Broglie) wave nature of atoms in a clear fashion. See Laser

Diffraction gratings

Diffraction gratings for atoms have been made by using either a standing wave of light or a slotted membrane. The standing light wave makes a phase grating (that is, it advances or retards alternate sections of the incident wavefront but does not absorb any of the atom wave), so that the transmitted intensity is high. This approach requires the complexity of a single-mode laser, and introduces the complication that the light acts differently on the various hyperfine states of the atom. The slotted membrane, however, absorbs (or backscatters) atoms which strike the grating bars, but does not significantly alter the phase of the transmitted atoms; it is therefore an amplitude grating. It works for any atom or molecule, regardless of internal quantum state, but with total transmission limited to about 40% by the opacity of the grating bars and requisite support structure. See Diffraction grating

Atom interferometers

Atom interferometers have been demonstrated through several different experimental routes, involving both microscopic fabricated structures and laser beams. These interferometers are the first examples of optical systems composed of the elements of atom optics like those discussed above. Atom interferometers, like optical interferometers, are well suited for application to a wide range of fundamental and applied scientific problems. Scientific experiments with atom interferometers divide naturally into three major categories: measurements of atomic and molecular properties, fundamental tests and demonstrations, and inertial effects.