Optics and Interferometry with Atoms and Molecules

A comprehensive review article covering recent acomplishments in atom and molecular optics and interferometry at MIT. Included is a introduction to our experimental apparatus, an overview of our techniques, and discussions of a number of notable experiments we have recently performed.

Published in Atom Interferometry, edited by Paul R. Berman (Academic Press, San Diego, 1997).

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Determining the Density Matrix of a Molecular Beam Using a Longitudinal Matter Wave Interferometer

Two separated oscillatory fields, if tuned to different frequencies (DSOF) can generate or interrogate longitudinal momentum coherences in a beam of two-state particles. We demonstrate that DSOF is an efficient method to determine the longitudinal density matrix of a particle beam.

To be Published in the Journal of Modern Optics, special issue on Quantum Tomography (in press)

Rotation Sensing with an Atom Interferometer

We have measured the phase shift induced by rotation of an atom interferometer at rates of -4 to +4 earth rates and obtained 1% agreement with the predicted Sagnac phase shift for atomic matter waves. The rotational rms noise of our interferometer was 42 milli-earth rates for 1 second of integration time, within 10% of shot noise. The high sensitivity and agreement of predicted and measured behavior suggest useful future scientific applications of atom interferometer inertial sensors.

Published in Physical Review Letters, February 3, 1997, Volume 78, Issue 5, pp. 760-763

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Photon Scattering from Atoms in an Atom Interferometer: Coherence Lost and Regained

We have scattered single photons from interfering de Broglie waves in an atom interferometer and observed contrast loss and revivals as the separation of the interfering paths at the point of scattering is increased. Additionally, we have demonstrated that the lost coherence can be recovered by observing only atoms that are correlated with photons emitted into a limited angular range.

Published in Physical Review Letters, November 20, 1995, Volume 75, Issue 21, pp. 3783-3787

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Optics and Interferometry with Na2 Molecules

We have produced an intense, pure beam of sodium molecules (Na2) by using light forces to separate the atomic and molecular species in a seeded supersonic beam. We used diffraction from a microfabricated grating to study the atomic and molecular sodium in the beam. Using three of these gratings, we constructed a molecule interferometer with fully separated beams and high contrast fringes. We measured both the real and imaginary parts of the index of refraction of neon gas for Na2 molecule de Broglie waves by inserting a gas cell in one arm of the interferometer.

Published in Physical Review Letters, June 12, 1995, Volume 74, Issue 24, pp. 4783-4786

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Index of Refraction of Various Gases for Sodium Matter Waves

By inserting a gas cell in one arm of an atom interferometer, we have measured both the attenuation and the phase shift of a sodium matter wave that passes through monatomic (He, Ne, Ar, Kr, and Xe) or molecular gases (N2, CO2, NH3, and H2O). This determines the complex index of refraction for Na matter waves and, more accurately, the ratio of the real to the imaginary part of the forward scattering amplitude. These measurements are compared with several semiclassical scattering models.

Published in Physical Review Letters, February 13, 1995, Volume 74, Issue 7, pp. 1043-1047

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