Observation of Atom Wave Phase Shifts Induced by Van Der Waals Atom-Surface Interactions

Perreault, John D.; Cronin, Alexander D.

doi:10.1103/physrevlett.95.133201

Cited by 72 publications

(58 citation statements)

References 23 publications

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“…We measured the phase shift in the zeroth order (Φ 0 ) due to transmission through a removable interaction grating (IG) with an interferometer [6]. The geometry of this experiment is shown in Figure 12, and permits us to study the interference fringes as a function of the IG position.…”

Section: Atom Interferometer Experimentsmentioning

confidence: 99%

“…A more detailed discussion of how to determine Φ 0 and C 3 from the measured phase shift is given in a separate entry of the CAMS conference proceedings by J.D. Perreault and in reference [6]. We also measured the phase difference Φ 2 − Φ 1 = 0.6±0.4 radians, by comparing the relative phases of four separate interferometers formed by adjacent pairs of the n = (−2, −1, 0, 1, 2) diffraction orders of the first interferometer grating.…”

Section: Atom Interferometer Experimentsmentioning

confidence: 99%

“…Top view of the atom interferometer. Three gratings make the interferometer and a removable interaction grating (IG) is used in [6] to study the phase shift Φ 0 caused by the van der Waals interaction. To compare our measurements with theory, we reviewed calculations of C 3 for sodium atoms and various surfaces as shown in Figure 15.…”

Section: Atom Interferometer Experimentsmentioning

confidence: 99%

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de Broglie wave phase shifts induced by surfaces closer than 25 nm

Cronin

Perreault

2005

J. Phys.: Conf. Ser.

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Abstract. Four atom optics experiments that each serve to measure atom-surface interactions near nanofabricated gratings are presented here. In these experiments atoms in a beam travel within 25 nm of a material grating bar, and the analysis incorporates phase shifts for the atomic de Broglie waves due to interactions betwen Na atoms and silicon nitride surfaces. One atom diffraction experiment determines the van der Waals coefficient C3 = 2.7±0.8 meVnm 3 , and one atom interferometer experiment determines C3 = 4±1 meVnm 3 . The results of all four experiments are consistent with the Lifshitz prediction that is explicitly calculated here for Nasilicon nitride to be C3 = 3.25 meVnm 3 . The four atom optics experiments and review of van der Waals theory are complemented by similar experiments using electron beams and analysis of image-charge effects. IntroductionTen nm away from a surface the potential energy for an atom is approximately 3 µeV, and for an electron it is about 10,000 times larger. More precisely, the van der Waals potential for sodium atoms and the image-charge potential for electrons both depend on the permittivity of the surface material; both potentials are also affected by surface charges, surface coatings, and surface geometry. Precise knowledge of the potential close to real surfaces is now needed for understanding atom optics experiments and nanotechnology devices, yet measurements of atomsurface interaction strengths have only been made for a few systems so far. Here we present four atom optics experiments that serve to measure the potential energy for atoms due to a surface located within 25 nm. Comparison to theoretical values of the non-retarded atom-surface van der Waals interaction will be made in the discussion.Our experiments are based on coherent transmission of sodium atom de Broglie waves through an array of 50 nm wide channels in a silicon nitride nanostructure grating. Transmitted atoms pass within 25 nm to a grating bar surface, and remain this close for only 10 −10 sec. Even in this short time, interactions with the channel walls modify the phase of the atom waves. Phase front curvature on the nanometer scale has the observed effect of modifying the phase Φ n and amplitude |A n | in each far-field diffraction order. We measured atom diffraction intensities and atom interferometer fringe phase shifts in order to determine the potential for sodium atoms induced by surfaces of silicon nitride.For comparison we used the same nanostructure gratings to diffract electron beams. Despite the 10,000 times larger potential energy (at 10 nm) due to image-charge effects, electron diffraction shows similar features to atom diffraction as a result of stronger interactions with the surface over shorter time scales.

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Section: Atom Interferometer Experimentsmentioning

confidence: 99%

Section: Atom Interferometer Experimentsmentioning

confidence: 99%

Section: Atom Interferometer Experimentsmentioning

confidence: 99%

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de Broglie wave phase shifts induced by surfaces closer than 25 nm

Cronin

Perreault

2005

J. Phys.: Conf. Ser.

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“…In these experiments the van der Waals (vdW) interaction [5] changed the relative intensities of the diffraction orders. More recently the atom wave phase shift Φ 0 induced by these grating structures 1 was measured directly using a sodium atom beam interferometer (IFM) [6]. The experimental setup is shown in Fig.…”

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confidence: 99%

Analysis of a material phase shifting element in an atom interferometer

Perreault

Cronin

2005

J. Phys.: Conf. Ser.

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The interaction of Na atoms with a surface was probed by inserting a nanofabricated material grating into one arm of an atom interferometer (IFM). This technique permits a direct measurement of the change in phase and coherence of matter waves as they pass within 25 nm of the grating bar surface. The practical concerns and challenges of making such a measurement are discussed here. Interference of spurious diffraction orders, IFM path overlap, and the partial obscuration of IFM beams are all important aspects of this experiment. The systematic effects that contribute to the measured phase shift and contrast are discussed.

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“…However, separated arms permit many additional uses. With tightly collimated atomic beams, separated arms were achieved and allowed precise measurements of atomic polarizabilities [44,68], phase shifts in atomic and molecular scattering [69], and atomsurface interactions [70].…”

Section: Arm Separationmentioning

confidence: 99%

Measuring Polarization Using a Bose-Einstein Condensate Interferometer

Deissler

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An atom interferometer using Bose-Einstein condensates has been implemented and is used to measure the dynamic polarizability of 87 Rb. An off-resonant standing-wave laser beam is used to manipulate the motion of atomic wavepackets in order to implement splitting and reflection operations. It is demonstrated that these operations can be performed with near unity fidelity.Interferometer times of up to 72 ms as well as arm separations of up to 0.42 mm are achieved experimentally.The primary limitation for guided-wave atom interferometers with a large arm separation is found to be the effect of the confining potential along the waveguide axis. Such a potential causes a spatially varying phase shift on the wavepackets as they propagate in the interferometer.Different parts of the cloud therefore interfere with different phases, leading to a reduction of the interferometer contrast. A model of the phase shifts on the wavepackets agrees well with the experimental data. In a different scheme in which the wavepackets oscillate freely in the confining potential, these phase shifts completely cancel. Interference is observed at times up to 0.9 s in this case, but with a fluctuating overall phase of the output, which is attributed to mechanical instabilities.Finally, the dynamic polarizability of 87 Rb is measured. A well-calibrated laser beam is applied to one atomic packet and not the other, inducing a differential phase shift. This technique requires relatively low laser intensity and works for arbitrary optical frequencies. For offresonant light, the ac polarizability is obtained with a statistical accuracy of 3% and a calibration ii uncertainty of 6%. On resonance, the dispersion-shaped behavior of the Stark shift is observed, but with a broadened linewidth that is attributed to multiple and collective light scattering effects. The resulting nonlinearity may prove useful for the production and control of squeezed quantum states. In general, this work also demonstrates the applicability of condensate interferometry to practical measurements.

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Observation of Atom Wave Phase Shifts Induced by Van Der Waals Atom-Surface Interactions

Cited by 72 publications

References 23 publications

de Broglie wave phase shifts induced by surfaces closer than 25 nm

de Broglie wave phase shifts induced by surfaces closer than 25 nm

Analysis of a material phase shifting element in an atom interferometer

Measuring Polarization Using a Bose-Einstein Condensate Interferometer

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