Theory of the light-force technique for measuring polarizabilities

Journal Article · Sun Jan 31 23:00:00 EST 1993 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.47.944· OSTI ID:6723463

Bonin, K D; Kadar-Kallen, M A ^[1]

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1. Department of Physics, Wake Forest University, Winston-Salem, North Carolina 27109-7507 (United States)

The theory of a method to measure electric-dipole polarizabilities is presented. The method uses two-stage laser ablation to produce a pulsed beam of atoms from a solid target. A pair of slits makes the velocity distribution of the atomic beam nonuniform in a way that is well characterized. The light-force technique uses the polarization forces experienced by an atom in the intense, inhomogeneous electromagnetic field of a standing-wave laser to change the velocity distribution of the atomic beam. The large forces cause measurable Doppler shifts in the resonant frequency of the atoms. These frequency shifts change the amount of absorption of resonant light, yielding information about the change in the velocity distribution of the atoms. The detailed shape of the final absorption distribution is polarizability dependent. In the classical picture of the light force, the standing-wave [ital electric] field induces a time-varying dipole moment in each atom. Each atom then experiences a Lorentz force due to coherent interaction of the oscillating dipole moment with the time-varying [ital magnetic] field. The quantum-mechanical picture corresponds to the Kapitza-Dirac effect for atoms: an atom absorbs a photon from one of the two beams which form the standing wave, and is then stimulated to emit this photon by the other, counterpropagating beam. This paper provides a classical treatment of the light force experienced by an atom in a standing-wave light field; the polarizability is treated quantum mechanically. The theory presented here can be applied to atoms with a scalar polarizability, such as rubidium, and to atoms with significant tensor components, such as uranium. Experimental results from application of the light-force technique to a measurement of the polarizability of rubidium are also presented.

• OSTI ID: 6723463
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 47:2; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664400* -- Experimentally Derived Information on Atomic & Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ACTINIDES
ALKALI METALS
ATOMS
DIPOLES
DOPPLER EFFECT
ELECTRIC DIPOLES
ELECTRICAL PROPERTIES
ELEMENTS
MEASURING METHODS
METALS
MULTIPOLES
PHYSICAL PROPERTIES
POLARIZABILITY
RADIATION PRESSURE
RUBIDIUM
STANDING WAVES
URANIUM