Velocity Rephased Longitudinal Momentum Coherences with Differentially Detuned Separated Oscillatory Fields

Smith, Edward T.; Dhirani, Al-Amin; Kokorowski, David A.; Rubenstein, Richard A.; Roberts, Tony; Yao, H.; Pritchard, David E.

doi:10.1103/physrevlett.81.1996

Cited by 20 publications

(17 citation statements)

References 15 publications

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“…This experiment may be considered as a photonic analogue of early days atom interferometry setups using detuned separated oscillatory fields as beam splitters. These experiments searched for off-diagonal terms of the density matrix of thermal atomic beams [19][20][21]. Non stationary beam splitters induce energy transfer and thus produce mixing of different energy components in the incoming particles' spectrum.…”

Section: Single Photon Beat Notesmentioning

confidence: 99%

Single photon beat note in an acousto-optic modulator-based interferometer

Mathevet

Chalopin

Massenot

2020

American Journal of Physics

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To cite this version:Renaud Mathevet, Benoît Chalopin, Sébastien Massenot. Single photon beat note in an acoustooptic modulator-based interferometer. AbstractWe present in the following a quantum optics experiment appropriate for advanced undergraduate students with former experience in quantum optics. It extends classical single photon setups to the time dependent domain. We demonstrate self-heterodyning of heralded single photons using a Mach-Zender like interferometer where beamsplitters are replaced by two acousto-optic modulators (AOMs). The single photon beat note is recorded over time at the frequency difference between the RF generators driving the AOMs, which makes it observable directly on a human time scale i. e. with periods above a fraction of a second. To compare with our observations, we tailor the standard quantum optics formalism for beam splitters to take into account the frequency shifts associated with the AOMs.

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Section: Single Photon Beat Notesmentioning

confidence: 99%

Single photon beat note in an acousto-optic modulator-based interferometer

Mathevet

Chalopin

Massenot

2020

American Journal of Physics

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“…However, significant advances have been made in experimental coherent control studies for unimolecular problems [1,2] and there are a number of possible approaches to preparing the states required for bimolecular control. These include extending a method successfully applied [17] to atoms in order to prepare the required correlated initial states, or state-selectively accelerating or decelerating molecules [18] that are in different internal state to achieve this result. Alternatively, we note that, for the case of the scattering of identical particles, preparation of the required states is straightforward [6].…”

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Coherent Control of Resonance-Mediated Reactions:F+HD

2004

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Cross sections resulting from scattering that proceeds via an intermediate resonance are shown to be exceptionally controllable using a coherent superposition of only two initial states. Full quantum computations on F+HD(v=0;j=0,1)-->H+DF, D+HF, which exhibits a resonance in one of the reactive channels, support the formal arguments, showing that control is indeed vast. In this case the ratio of reactive integral cross sections can be altered by a factor of 62 (compared to a noncoherent factor of only 3.3), while the ratio of reactive differential cross sections can be altered by a factor of over 6000 (compared to a noncoherent factor of less than 7). These results constitute the first prediction of extensive quantum control in a collisional process.

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“…In this experiment, we used the differentially detuned separated oscillatory field (DSOF) longitudinal interferometer of Ref. [14] as the time-dependent apparatus necessary to study the relative phases of different energy components and thereby to search for ODEs. We first studied intentionally applied ODEs created via amplitude modulation of the beam [14,15] for calibration purposes.…”

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confidence: 99%

“…[14] as the time-dependent apparatus necessary to study the relative phases of different energy components and thereby to search for ODEs. We first studied intentionally applied ODEs created via amplitude modulation of the beam [14,15] for calibration purposes. Our search then employed this calibration to place an upper bound on the magnitude of the ODEs created by our source.To determine the range of our search, we measured the velocity (and hence the energy) distribution of atoms emitted from our source, using the technique of separated oscillatory fields, and found a nearly Gaussian distribution with a mean frequency of 3.4 3 10 13 Hz (1090 m͞s) and an rms width of 2.2 3 10 12 Hz (35 m͞s).…”

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Search for Off-Diagonal Density Matrix Elements for Atoms in a Supersonic Beam

et al. 1999

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We demonstrate the absence of off-diagonal elements for the density matrix of a supersonic Na atomic beam, thus showing that there are no coherent wave packets emerging from this source. We used a differentially detuned separated oscillatory field longitudinal interferometer to search for off-diagonal density matrix elements in the longitudinal energy͞momentum basis. Our study places a stringent lower bound on their possible size over an off-diagonal energy range from 0 to 100 kHz.[S0031-9007(99)08620-2] PACS numbers: 03.75. Dg, 39.10. + j Atomic beam experiments, from early resonance studies [1] to modern work in atom optics and interferometry [2], invariably make assumptions about longitudinal atomic motion (e.g., classical, wave packet, plane wave). Despite some theoretical discussion [3][4][5][6][7], to date no experimental test has been performed which can discriminate between these alternative descriptions. This omission, along with the development of novel atomic sources with interesting coherence properties (e.g., cold atom beams, atom lasers [8]), demonstrates the need for experiments which probe not only the transverse [9] but also the longitudinal quantum state of atomic beams.In this Letter, we present the first experimental limits on the size of off-diagonal elements (ODEs) in the longitudinal energy͞momentum density matrix characterizing a supersonic atomic beam. This demonstration, together with a determination of the beam's energy distribution, constitutes a measurement of the density matrix, the most complete possible description of the longitudinal quantum state of the ensemble of atoms in the atomic beam.In the energy basis hn ͑hk͒ 2 ͞2m, the time dependence of any density matrix element is given by r͑n 0 , n 00 , t͒ r o ͑n 0 , n 0 1 n coh ͒e i2pn coh ͑t2t o ͒ , (1) where n coh ϵ n 00 2 n 0 , t o is an initial reference time and r o r͑t o ͒. Here n coh is the distance off the diagonal of the density matrix, while n 0 is the coordinate parallel to the diagonal.It is tempting to consider an atomic beam source as emitting a stream of wave packets, each a coherent superposition of various longitudinal momenta, implying nonzero ODEs. However, the density matrix for an ensemble of such atoms contains an average over the randomly distributed initial time t o of each wave packet, causing all ODEs to be zero if the source is temporally stationary (e.g., an effusive atom oven in thermal equilibrium).For a nonstationary source, the ensemble average need not make all ODEs zero because the distribution of t o 's can be nonrandom. Thus nonstationary sources can contain coherent, physically observable wave packets. Our beam is created via supersonic expansion of Na seeded in ϳ2 atm of Ar, which passes through a sharp-edged beam skimmer with a hole diameter of d 0.5 mm. This arrangement, which yields a sound velocity at the skimmer of y s ϳ 50 m͞s, may contain nonstationary hydrodynamic instabilities. These could create a timedependent amplitude modulation of the beam, and, hence, nonzero ODEs, with expecte...

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Velocity Rephased Longitudinal Momentum Coherences with Differentially Detuned Separated Oscillatory Fields

Cited by 20 publications

References 15 publications

Single photon beat note in an acousto-optic modulator-based interferometer

Single photon beat note in an acousto-optic modulator-based interferometer

Coherent Control of Resonance-Mediated Reactions:F+HD

Search for Off-Diagonal Density Matrix Elements for Atoms in a Supersonic Beam

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