Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Physical Review Letters

Ramsey interference fringes in radiatively assisted collisions of K Rydberg atoms

Michael J. Renn, Thomas F. Gallagher

Published Oct 1, 1991• 10 citations
Publisher

Abstract

When resonant collisional energy transfer occurs in a radiation field of frequency comparable to the inverse of the collision time, Ramsey interference fringes are observed in the cross section. At low frequencies the fringes are phase dependent, but at high frequencies they are not. The fringes may be understood with a quasistatic field description, which ties together the low- and high-frequency regimes.

DOI
10.1103/physrevlett.67.2287

Related papers

Frequency evolution of radiatively assisted collisions of K Rydberg atoms

Michael J. Renn, D. S. Thomson, Thomas F. Gallagher

Ramsey interference fringes are observed in the line shape of resonant Rydberg-atom--Rydberg-atom collisions occurring in the presence of a radiation field of frequency comparable to the inverse of the collision time. At low frequencies the fringes are phase dependent, but at high frequencies they are not. We present a theoretical interpretation based on a quasistatic field description which connects the low- and high-frequency regimes. In the high-frequency regime, this model gives results equivalent to those obtained using a ``dressed-atom'' approach.

Physical Review A•Jan 1, 1994•6 citations

Radiatively assisted collisions of K Rydberg atoms

D. S. Thomson, Michael J. Renn, Thomas F. Gallagher

We have observed radiatively assisted collisions between velocity-selected K Rydberg atoms in radio-frequency (rf) fields. The low relative velocity of the atoms leads to long collision times, or equivalently, narrow, 1-MHz, collisional resonances. We have carried out systematic measurements with rf fields in the strong-field regime, and have shown that the cross sections agree quantitatively with the predictions of the strong-field theory. We have also shown experimentally and theoretically that the sum over m of the cross sections for m photon-assisted cross sections is larger than the resonant-collision cross section in the absence of a rf field.

Physical Review A•Jan 1, 1992•6 citations

Ramsey fringes in laser-assisted collisions

P. R. Berman, Arturo Bambini

It is shown theoretically that Ramsey fringes can be produced when a laser-assisted reaction of the form ${\mathrm{A}}_{2}$+${\mathrm{A}}_{1}^{\ensuremath{'}}$+\ensuremath{\Elzxh}\ensuremath{\Omega}\ensuremath{\rightarrow}${\mathrm{A}}_{1}$+${\mathrm{A}}_{2}^{\ensuremath{'}}$ is driven by a pair of ultrafast radiation pulses, each of whose temporal widths is less than the duration ${\mathrm{\ensuremath{\tau}}}_{\mathrm{c}}$ of a collision between the A and A\ensuremath{'} atoms. The excitation profile of the laser-assisted collision is calculated as a function of detuning of the laser field frequency from the initial- to final-state transition frequency. For radiation pulses separated by time T, Ramsey fringes appear separated in frequency by ${\mathrm{T}}^{\mathrm{\ensuremath{-}}1}$. The modulation depth and shift of the central Ramsey fringe as a function of (T/${\mathrm{\ensuremath{\tau}}}_{\mathrm{c}}$) provide information about the collisional interaction. Both the weak- and strong-field regions are considered and comparison with laser-assisted collisions using excitation pulses having temporal widths greater than ${\mathrm{\ensuremath{\tau}}}_{\mathrm{c}}$ is made.

Physical Review A•Jul 1, 1994•1 citation

Resonant collisional energy transfer with Rydberg atoms

Thomas F. Gallagher

Resonant collisional energy transfer can be studied in uprecedented detail using Rydberg atoms. Using the dependence of the energy level spacing on principal quantum number it is possible to examine resonant energy transfer in collisions with molecules. Finer control of the level spacing is possible by varying the level spacings with an electric field. Using this approach it is possible to observe sharply resonant collisions between Rydberg atoms. They are resonant dipole-dipole collisions which have cross sections orders of magnitude larger than the geometric cross sections of the colliding Rydberg atoms. These collisions are interesting in themselves; for example, they exhibit intracollisional interference, and it is possible to know when individual collisions begin and end. Perhaps the most interesting aspect of these collisions is that, because of the large dipole moments of the Rydberg atoms, they are easily controlled by microwave and radio frequency fields.

Bulletin of the American Physical Society•May 1, 1996•0 citations

Transform-limited collisions of K Rydberg atoms

D. S. Thomson, Michael J. Renn, Thomas F. Gallagher

By reducing the collision velocity of Rydberg atoms in resonant energy-transfer collisions, we have observed collisional resonances as narrow as 1 MHz, or collision times as long as 1.0 \ensuremath{\mu}s. Restricting the collision to a time less than the natural collision time results in transform broadening of the resonances, allowing us to know when an individual collision begins and ends. The latter point is verified by observing the dependence of the collision line shape on the phase of an oscillating field of frequency equal to the width of the collisional resonance.

Physical Review Letters•Dec 24, 1990•15 citations

RADIATIVE COLLISIONS IN A STRONG FIELD REGIME

P. Pillet, Ravinder Kachru, Nam Huu Tran +2 more

The process of resonant collisional energy transfer between Rydberg atoms provides an ideal starting point for systematic studies of radiatively assisted collisions. In fact using modest, readily available microwave sources it is straightforward to enter the strong field regime for such processes.

Le Journal de Physique Colloques•Jan 1, 1985•1 citation
When resonant collisional energy transfer occurs in a radiation field of frequency comparable to the inverse of the collision time, Ramsey interference fringes are observed in the cross section. At low frequencies the fringes are phase dependent, but at high frequencies they are not. The fringes may be understood with a quasistatic field description, which ties together the low- and high-frequency regimes.
Ramsey interference fringes are observed in the line shape of resonant Rydberg-atom--Rydberg-atom collisions occurring in the presence of a radiation field of frequency comparable to the inverse of the collision time. At low frequencies the fringes are phase dependent, but at high frequencies they are not. We present a theoretical interpretation based on a quasistatic field description which connects the low- and high-frequency regimes. In the high-frequency regime, this model gives results equivalent to those obtained using a ``dressed-atom'' approach.
We have observed radiatively assisted collisions between velocity-selected K Rydberg atoms in radio-frequency (rf) fields. The low relative velocity of the atoms leads to long collision times, or equivalently, narrow, 1-MHz, collisional resonances. We have carried out systematic measurements with rf fields in the strong-field regime, and have shown that the cross sections agree quantitatively with the predictions of the strong-field theory. We have also shown experimentally and theoretically that the sum over m of the cross sections for m photon-assisted cross sections is larger than the resonant-collision cross section in the absence of a rf field.
It is shown theoretically that Ramsey fringes can be produced when a laser-assisted reaction of the form A2{\mathrm{A}}_{2}A2​+${\mathrm{A}}_{1}^{\ensuremath{'}}$+\ensuremath{\Elzxh}\ensuremath{\Omega}\ensuremath{\rightarrow}A1{\mathrm{A}}_{1}A1​+${\mathrm{A}}_{2}^{\ensuremath{'}}$ is driven by a pair of ultrafast radiation pulses, each of whose temporal widths is less than the duration ${\mathrm{\ensuremath{\tau}}}_{\mathrm{c}}$ of a collision between the A and A\ensuremath{'} atoms. The excitation profile of the laser-assisted collision is calculated as a function of detuning of the laser field frequency from the initial- to final-state transition frequency. For radiation pulses separated by time T, Ramsey fringes appear separated in frequency by ${\mathrm{T}}^{\mathrm{\ensuremath{-}}1}$. The modulation depth and shift of the central Ramsey fringe as a function of (T/${\mathrm{\ensuremath{\tau}}}_{\mathrm{c}}$) provide information about the collisional interaction. Both the weak- and strong-field regions are considered and comparison with laser-assisted collisions using excitation pulses having temporal widths greater than ${\mathrm{\ensuremath{\tau}}}_{\mathrm{c}}$ is made.
Resonant collisional energy transfer can be studied in uprecedented detail using Rydberg atoms. Using the dependence of the energy level spacing on principal quantum number it is possible to examine resonant energy transfer in collisions with molecules. Finer control of the level spacing is possible by varying the level spacings with an electric field. Using this approach it is possible to observe sharply resonant collisions between Rydberg atoms. They are resonant dipole-dipole collisions which have cross sections orders of magnitude larger than the geometric cross sections of the colliding Rydberg atoms. These collisions are interesting in themselves; for example, they exhibit intracollisional interference, and it is possible to know when individual collisions begin and end. Perhaps the most interesting aspect of these collisions is that, because of the large dipole moments of the Rydberg atoms, they are easily controlled by microwave and radio frequency fields.
By reducing the collision velocity of Rydberg atoms in resonant energy-transfer collisions, we have observed collisional resonances as narrow as 1 MHz, or collision times as long as 1.0 \ensuremath{\mu}s. Restricting the collision to a time less than the natural collision time results in transform broadening of the resonances, allowing us to know when an individual collision begins and ends. The latter point is verified by observing the dependence of the collision line shape on the phase of an oscillating field of frequency equal to the width of the collisional resonance.