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

European Quantum Electronics Conference (EQEC)

New Subrecoil Laser Cooling Scheme for Neutral Atoms with a Non-Degenerated Ground Level

Norbert Leinfellner, I. E. Mazets, Boris G. Matisov

Published Jan 1, 1996• 0 citations
Publisher

Abstract

We present a new scheme for ID subrecoil laser cooling by velocity-selective coherent population trapping of even-even isotopes of elements found in the second group of the periodical table, particularily, zaaHg and 40Ca. The scheme envolves the transitions (a) between the ground state with the total angular momentum Pg = 0 and the excited one with Fe = 1, @) between the latter state and the second excited one with Fe* = 2. The second transition belongs to the infrared region and has a width much smaller than the transition from the ground state. The lower transition is driven by two counterpropagating o+ and U- polarized running waves. The laser beam applied in the perpendicular direction is a linearily polarized standing wave exciting the

DOI
10.1109/eqec.1996.561885

Related papers

Coherent Trapping Subrecoil Cooling in Two Dimensions Aided by a Force

Francesco Mauri, E. Arimondo

Two-dimensional laser cooling based on velocity-selective coherent population trapping is investigated theoretically for the J = 1 ↔ J = 1 atomic transition. Wave vectors and polarizations of three laser beams are chosen to realize a coherent superposition of three degenerate ground states. For the first time forces related to Doppler and interference effects are combined with coherent population trapping to realize a very efficient cooling. Numerical solutions are presented for laser cooling of helium atoms.

Europhysics Letters (EPL)•Oct 21, 1991•29 citations

Several asymptotic subrecoil laser-cooling behaviors in arbitrary degenerate Λ systems

Hong Yuan Ling

Subrecoil cooling can be achieved in three-level \ensuremath{\Lambda}-type atoms subject to counterpropagating laser beams via velocity-selective coherent population trapping [A. Aspect et al., J. Opt. Soc. Am. B 6, 2112 (1989)]. This process leads to narrow peaks in the ground but a flat structure in the excited atomic momentum distributions. By taking advantage of this difference, we construct several analytical functions from which the main cooling features (with the exception of the scaling law about the fraction of subrecoil cooled atoms) can be approximated under arbitrary parameters. This method allows us to generalize the peak-momentum width from symmetric to arbitrary degenerate \ensuremath{\Lambda} systems, and to discuss analytically the small dependence of the momentum distributions on the laser detuning near the two-photon resonance.

Physical Review A•May 1, 1999•5 citations

Subrecoil Laser Cooling with Adiabatic Transfer

Tilman Esslinger, F. Sander, Matthias Weidemüller +2 more

We demonstrate subrecoil cooling of rubidium atoms by velocity-selective coherent population trapping. By adiabatic transfer of the cooled atoms into a spin polarized single momentum state we show the coherence of the trapped state. Our cooling scheme takes advantage of the rubidium hyperfine structure to integrate subrecoil and sub-Doppler cooling. Starting from an initial velocity distribution of twice the recoil temperature $[{T}_{\mathrm{rec}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}(\ensuremath{\Elzxh}k{)}^{2}{/k}_{B}M]$, we cool down to 100 nK $(\ensuremath{\approx}\frac{1}{3}{T}_{\mathrm{rec}})$ within 1 ms, while almost completely suppressing the diffusive heating of velocity-selective coherent population trapping.

Physical Review Letters•Apr 1, 1996•56 citations

Polarization-gradient-assisted subrecoil cooling: Quantum calculations in one dimension

P. Marte, Ralph Dum, Richard Taïeb +3 more

We present a fully quantum-mechanical analysis of laser cooling of an angular momentum ${\mathit{J}}_{\mathit{g}}$=1 to ${\mathit{J}}_{\mathit{e}}$=1 transition in a laser configuration consisting of two counterpropagating linearly polarized laser beams. The essential feature of this configuration is the coexistence of velocity-selective coherent population trapping (VSCPT) and polarization-gradient cooling. The role of polarization-gradient cooling is to provide (i) for short interaction times ``precooling'' of the initial momentum distribution and (ii) in the long-time limit ``confinement of velocities.'' This eventually leads to a larger number of atoms being captured in the dark state when compared with the schme of Aspect et al. [Phys. Rev. Lett. 61, 826 (1988)]. We find that the optimum parameter values for polarization-gradient cooling and VSCPT are in a completely different parameter regime: polarization-gradient cooling works best off resonance and for low intensities, while VSCPT works best on resonance. We can combine the advantages of polarization-gradient cooling and VSCPT in a scheme where we cycle in time between the optimum cooling parameters for both cooling mechanisms.

Physical Review A•Jun 1, 1994•64 citations

Two-Dimensional Subrecoil Laser Cooling

John Lawall, F. Bardou, Bruno Saubaméa +4 more

We report the first observation of subrecoil laser cooling in two dimensions by velocity selective coherent population trapping. We have compressed the momentum distribution of a cloud of trapped metastable helium atoms along two orthogonal axes to $\ensuremath{\delta}p=\frac{\ensuremath{\hbar}k}{4}$, where $\ensuremath{\hbar}k$ is the photon momentum. The corresponding temperature, 16 times below the single-photon recoil temperature, is 250 nK. Atoms are pumped into a nonabsorbing state exhibiting four well-resolved momentum peaks with subrecoil widths. The momentum space density in the peaks is significantly greater than that in the uncooled distribution.

Physical Review Letters•Oct 3, 1994•113 citations

Laser cooling of Rydberg atoms by velocity-selective coherent population trapping

Jingzhong Guo, Eugeny Korsunsky, E. Arimondo

One-dimensional velocity-selective coherent population trapping (VSCPT) in a cascade atomic configuration, with the second excited level a Rydberg state, is investigated through numerical calculations. The trapping efficiency for the case of travelling wave lasers is derived from the solution of the optical Bloch equations. For excitation by bichromatic standing waves, the energy-band approach is applied. Although the cooling process is limited by the spontaneous emission decay of the Rydberg state, the coexistence of polarization-gradient cooling and VSCPT in the case of standing waves allows the preparation of the majority of the atomic population in a cold Rydberg state.

Quantum and Semiclassical Optics Journal of the European Optical Society Part B•Jun 1, 1996•3 citations
We present a new scheme for ID subrecoil laser cooling by velocity-selective coherent population trapping of even-even isotopes of elements found in the second group of the periodical table, particularily, zaaHg and 40Ca. The scheme envolves the transitions (a) between the ground state with the total angular momentum Pg = 0 and the excited one with Fe = 1, @) between the latter state and the second excited one with Fe* = 2. The second transition belongs to the infrared region and has a width much smaller than the transition from the ground state. The lower transition is driven by two counterpropagating o+ and U- polarized running waves. The laser beam applied in the perpendicular direction is a linearily polarized standing wave exciting the
Two-dimensional laser cooling based on velocity-selective coherent population trapping is investigated theoretically for the J = 1 ↔ J = 1 atomic transition. Wave vectors and polarizations of three laser beams are chosen to realize a coherent superposition of three degenerate ground states. For the first time forces related to Doppler and interference effects are combined with coherent population trapping to realize a very efficient cooling. Numerical solutions are presented for laser cooling of helium atoms.
Subrecoil cooling can be achieved in three-level \ensuremath{\Lambda}-type atoms subject to counterpropagating laser beams via velocity-selective coherent population trapping [A. Aspect et al., J. Opt. Soc. Am. B 6, 2112 (1989)]. This process leads to narrow peaks in the ground but a flat structure in the excited atomic momentum distributions. By taking advantage of this difference, we construct several analytical functions from which the main cooling features (with the exception of the scaling law about the fraction of subrecoil cooled atoms) can be approximated under arbitrary parameters. This method allows us to generalize the peak-momentum width from symmetric to arbitrary degenerate \ensuremath{\Lambda} systems, and to discuss analytically the small dependence of the momentum distributions on the laser detuning near the two-photon resonance.
We demonstrate subrecoil cooling of rubidium atoms by velocity-selective coherent population trapping. By adiabatic transfer of the cooled atoms into a spin polarized single momentum state we show the coherence of the trapped state. Our cooling scheme takes advantage of the rubidium hyperfine structure to integrate subrecoil and sub-Doppler cooling. Starting from an initial velocity distribution of twice the recoil temperature $[{T}_{\mathrm{rec}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}(\ensuremath{\Elzxh}k{)}^{2}{/k}_{B}M]$, we cool down to 100 nK $(\ensuremath{\approx}\frac{1}{3}{T}_{\mathrm{rec}})$ within 1 ms, while almost completely suppressing the diffusive heating of velocity-selective coherent population trapping.
We present a fully quantum-mechanical analysis of laser cooling of an angular momentum Jg{\mathit{J}}_{\mathit{g}}Jg​=1 to Je{\mathit{J}}_{\mathit{e}}Je​=1 transition in a laser configuration consisting of two counterpropagating linearly polarized laser beams. The essential feature of this configuration is the coexistence of velocity-selective coherent population trapping (VSCPT) and polarization-gradient cooling. The role of polarization-gradient cooling is to provide (i) for short interaction times ``precooling'' of the initial momentum distribution and (ii) in the long-time limit ``confinement of velocities.'' This eventually leads to a larger number of atoms being captured in the dark state when compared with the schme of Aspect et al. [Phys. Rev. Lett. 61, 826 (1988)]. We find that the optimum parameter values for polarization-gradient cooling and VSCPT are in a completely different parameter regime: polarization-gradient cooling works best off resonance and for low intensities, while VSCPT works best on resonance. We can combine the advantages of polarization-gradient cooling and VSCPT in a scheme where we cycle in time between the optimum cooling parameters for both cooling mechanisms.
We report the first observation of subrecoil laser cooling in two dimensions by velocity selective coherent population trapping. We have compressed the momentum distribution of a cloud of trapped metastable helium atoms along two orthogonal axes to $\ensuremath{\delta}p=\frac{\ensuremath{\hbar}k}{4}$, where $\ensuremath{\hbar}k$ is the photon momentum. The corresponding temperature, 16 times below the single-photon recoil temperature, is 250 nK. Atoms are pumped into a nonabsorbing state exhibiting four well-resolved momentum peaks with subrecoil widths. The momentum space density in the peaks is significantly greater than that in the uncooled distribution.
One-dimensional velocity-selective coherent population trapping (VSCPT) in a cascade atomic configuration, with the second excited level a Rydberg state, is investigated through numerical calculations. The trapping efficiency for the case of travelling wave lasers is derived from the solution of the optical Bloch equations. For excitation by bichromatic standing waves, the energy-band approach is applied. Although the cooling process is limited by the spontaneous emission decay of the Rydberg state, the coexistence of polarization-gradient cooling and VSCPT in the case of standing waves allows the preparation of the majority of the atomic population in a cold Rydberg state.