arXiv:1707.09709 · Physical Review A

Laser cooling of Rb85 atoms to the recoil-temperature limit

Chang Cang Huang, Pei-Chen Kuan, Shau-Yu Lan

Published Feb 1, 2018• 11 citations

Abstract

We demonstrate the laser cooling of $^{85}\mathrm{Rb}$ atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme [Kerman et al., Phys. Rev. Lett. 84, 439 (2000)], where a fast cooling of atoms to an auxiliary state is followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at a Lamb-Dicke parameter $\ensuremath{\eta}=0.45$ and show the cooling of spin-polarized $^{85}\mathrm{Rb}$ atoms to the recoil temperature in both dimensions within 2.4 ms with the aid of adiabatic cooling.

DOI: 10.1103/physreva.97.023403

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arXiv:1707.09709 · Physical Review A

Laser cooling of Rb85 atoms to the recoil-temperature limit

Chang Cang Huang, Pei-Chen Kuan, Shau-Yu Lan

Published Feb 1, 2018• 11 citations

arXiv HTML PDF

Abstract

We demonstrate the laser cooling of

^{85}\mathrm{Rb}

atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme [Kerman et al., Phys. Rev. Lett. 84, 439 (2000)], where a fast cooling of atoms to an auxiliary state is followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at a Lamb-Dicke parameter

\ensuremath{\eta}=0.45

and show the cooling of spin-polarized

^{85}\mathrm{Rb}

atoms to the recoil temperature in both dimensions within 2.4 ms with the aid of adiabatic cooling.

DOI: 10.1103/physreva.97.023403

Related papers

Efficient Laser Cooling of 85Rb Atoms to the Recoil Temperature Limit

Chang Cang Huang, Pei-Chen Kuan, Shau-Yu Lan

We demonstrate laser cooling of 85Rb atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme, Kerman el al., Phys. Rev. Lett. 84, 439 (2000), where a fast cooling of atoms to an auxiliary state followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at Lamb-Dicke parameter eta=0.45 and show the cooling of spin-polarized 85Rb atoms to the recoil temperature in both dimension within 2.4 ms with 90% of initial atom numbers.We demonstrate laser cooling of 85Rb atoms in a two-dimensional optical lattice. We follow the two-step degenerate Raman sideband cooling scheme, Kerman el al., Phys. Rev. Lett. 84, 439 (2000), where a fast cooling of atoms to an auxiliary state followed by a slow cooling to a dark state. This method has the advantage of independent control of the heating rate and cooling rate from the optical pumping beam. We operate the lattice at Lamb-Dicke parameter eta=0.45 and show the cooling of spin-polarized 85Rb atoms to the recoil temperature in both dimension within 2.4 ms with 90% of initial atom numbers.

Jul 31, 20171 citation

Degenerate Raman sideband cooling of K40 atoms

Elad Zohar, Yanay Florshaim, Oded Zilberman +2 more

We report on the implementation of degenerate Raman sideband cooling of $^{40}\mathrm{K}$ atoms. The scheme incorporates a three-dimensional (3D) optical lattice, which confines the atoms and drives the Raman transitions. The optical cooling cycle is closed by two optical pumping beams. The wavelength of the laser beams forming the lattice is close to the ${\mathrm{D}}_{2}$ atomic transition, while the optical pumping is operated near the ${\mathrm{D}}_{1}$ transition. With this cooling method, we achieve a temperature of $\ensuremath{\sim}1\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{K}$ of a cloud with $\ensuremath{\sim}{10}^{7}$ atoms. This corresponds to a phase space density of $\ensuremath{\ge}{10}^{\ensuremath{-}3}$. Moreover, the fermionic ensemble is spin polarized to conditions which are favorable for subsequent evaporative cooling. We study the dependence of the cooling scheme on several parameters, including the applied magnetic field and the detuning, duration, and intensity profile of the optical pumping beams. Adding this optical cooling stage to current Fermi gas experiments can improve the final conditions and increase the data rate.We report on the implementation of degenerate Raman sideband cooling of $^{40}\mathrm{K}$ atoms. The scheme incorporates a three-dimensional (3D) optical lattice, which confines the atoms and drives the Raman transitions. The optical cooling cycle is closed by two optical pumping beams. The wavelength of the laser beams forming the lattice is close to the ${\mathrm{D}}_{2}$ atomic transition, while the optical pumping is operated near the ${\mathrm{D}}_{1}$ transition. With this cooling method, we achieve a temperature of $\ensuremath{\sim}1\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{K}$ of a cloud with $\ensuremath{\sim}{10}^{7}$ atoms. This corresponds to a phase space density of $\ensuremath{\ge}{10}^{\ensuremath{-}3}$. Moreover, the fermionic ensemble is spin polarized to conditions which are favorable for subsequent evaporative cooling. We study the dependence of the cooling scheme on several parameters, including the applied magnetic field and the detuning, duration, and intensity profile of the optical pumping beams. Adding this optical cooling stage to current Fermi gas experiments can improve the final conditions and increase the data rate.

arXiv:2208.05160Physical Review ADec 23, 20228 citations

Dark-state sideband cooling in an atomic ensemble

Chang Cang Huang, Shijie Chai, Shau-Yu Lan

We utilize the dark state in a $\mathrm{\ensuremath{\Lambda}}$-type three-level system to cool an ensemble of $^{85}\mathrm{Rb}$ atoms in an optical lattice [Morigi et al., Phys. Rev. Lett. 85, 4458 (2000)]. The common suppression of the carrier transition of atoms with different vibrational frequencies allows them to reach a subrecoil temperature of 100 nK after being released from the optical lattice. A nearly zero vibrational quantum number is determined from the time-of-flight measurements and adiabatic expansion process. The features of sideband cooling are examined in various parameter spaces. Our results show that dark-state sideband cooling is a simple and compelling method for preparing a large ensemble of atoms into their vibrational ground state of a harmonic potential and can be generalized to different species of atoms and molecules for studying ultracold physics that demands recoil temperature and below.We utilize the dark state in a $\mathrm{\ensuremath{\Lambda}}$-type three-level system to cool an ensemble of $^{85}\mathrm{Rb}$ atoms in an optical lattice [Morigi et al., Phys. Rev. Lett. 85, 4458 (2000)]. The common suppression of the carrier transition of atoms with different vibrational frequencies allows them to reach a subrecoil temperature of 100 nK after being released from the optical lattice. A nearly zero vibrational quantum number is determined from the time-of-flight measurements and adiabatic expansion process. The features of sideband cooling are examined in various parameter spaces. Our results show that dark-state sideband cooling is a simple and compelling method for preparing a large ensemble of atoms into their vibrational ground state of a harmonic potential and can be generalized to different species of atoms and molecules for studying ultracold physics that demands recoil temperature and below.

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Degenerate Raman sideband cooling of K39

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arXiv:1612.02309Physical Review AMar 15, 201724 citations

Two-dimensional sideband Raman cooling and Zeeman-state preparation in an optical lattice

А. В. Тайченачев, Anatolii M Tumaikin, Valeriy I. Yudin +1 more

A method of sideband Raman cooling to the vibrational ground state of the $m=0$ Zeeman sublevel in a far-detuned two-dimensional optical lattice is proposed. In our scheme, the Raman coupling between vibrational manifolds of the adjacent Zeeman sublevels is shifted to the red sideband due to the ac Stark effect induced by a weak pump field. Thus cooling and optical pumping to $m=0$ are achieved by purely optical means with coplanar cw laser beams. The optical lattice and cooling parameters are estimated in the framework of simple theoretical models. An application of the transverse sideband cooling method to frequency standards is discussed. Coherent population trapping for the sideband Raman transitions between the degenerate vibrational levels is predicted.A method of sideband Raman cooling to the vibrational ground state of the $m=0$ Zeeman sublevel in a far-detuned two-dimensional optical lattice is proposed. In our scheme, the Raman coupling between vibrational manifolds of the adjacent Zeeman sublevels is shifted to the red sideband due to the ac Stark effect induced by a weak pump field. Thus cooling and optical pumping to $m=0$ are achieved by purely optical means with coplanar cw laser beams. The optical lattice and cooling parameters are estimated in the framework of simple theoretical models. An application of the transverse sideband cooling method to frequency standards is discussed. Coherent population trapping for the sideband Raman transitions between the degenerate vibrational levels is predicted.

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Motional-ground-state cooling outside the Lamb-Dicke regime

Yichao Yu, Nicholas R. Hutzler, Jessie T. Zhang +4 more

We report Raman sideband cooling of a single sodium atom to its three-dimensional motional ground state in an optical tweezer. Despite a large Lamb-Dicke parameter, high initial temperature, and large differential light shifts between the excited state and the ground state, we achieve a ground-state population of 93.5(7)% after 53 ms of cooling. Our technique includes addressing high-order sidebands, where several motional quanta are removed by a single laser pulse, and fast modulation of the optical tweezer intensity. We demonstrate that Raman sideband cooling to the three-dimensional motional ground state is possible, even without tight confinement and low initial temperature.We report Raman sideband cooling of a single sodium atom to its three-dimensional motional ground state in an optical tweezer. Despite a large Lamb-Dicke parameter, high initial temperature, and large differential light shifts between the excited state and the ground state, we achieve a ground-state population of 93.5(7)% after 53 ms of cooling. Our technique includes addressing high-order sidebands, where several motional quanta are removed by a single laser pulse, and fast modulation of the optical tweezer intensity. We demonstrate that Raman sideband cooling to the three-dimensional motional ground state is possible, even without tight confinement and low initial temperature.

arXiv:1708.03296Physical Review AJun 28, 201845 citations

We demonstrate the laser cooling of

^{85}\mathrm{Rb}

\ensuremath{\eta}=0.45

and show the cooling of spin-polarized

^{85}\mathrm{Rb}

atoms to the recoil temperature in both dimensions within 2.4 ms with the aid of adiabatic cooling.

We report on the implementation of degenerate Raman sideband cooling of

^{40}\mathrm{K}

atoms. The scheme incorporates a three-dimensional (3D) optical lattice, which confines the atoms and drives the Raman transitions. The optical cooling cycle is closed by two optical pumping beams. The wavelength of the laser beams forming the lattice is close to the

{\mathrm{D}}_{2}

atomic transition, while the optical pumping is operated near the

{\mathrm{D}}_{1}

transition. With this cooling method, we achieve a temperature of $\ensuremath{\sim}1\phantom{\rule{0.16em}{0ex}}\ensuremath{\mu}\mathrm{K}$ of a cloud with $\ensuremath{\sim}{10}^{7}$ atoms. This corresponds to a phase space density of $\ensuremath{\ge}{10}^{\ensuremath{-}3}$. Moreover, the fermionic ensemble is spin polarized to conditions which are favorable for subsequent evaporative cooling. We study the dependence of the cooling scheme on several parameters, including the applied magnetic field and the detuning, duration, and intensity profile of the optical pumping beams. Adding this optical cooling stage to current Fermi gas experiments can improve the final conditions and increase the data rate.

We utilize the dark state in a $\mathrm{\ensuremath{\Lambda}}$-type three-level system to cool an ensemble of

^{85}\mathrm{Rb}

atoms in an optical lattice [Morigi et al., Phys. Rev. Lett. 85, 4458 (2000)]. The common suppression of the carrier transition of atoms with different vibrational frequencies allows them to reach a subrecoil temperature of 100 nK after being released from the optical lattice. A nearly zero vibrational quantum number is determined from the time-of-flight measurements and adiabatic expansion process. The features of sideband cooling are examined in various parameter spaces. Our results show that dark-state sideband cooling is a simple and compelling method for preparing a large ensemble of atoms into their vibrational ground state of a harmonic potential and can be generalized to different species of atoms and molecules for studying ultracold physics that demands recoil temperature and below.

We report on a realization of sub-Doppler laser cooling of

^{39}\mathrm{K}

atoms using degenerate three-dimensional Raman sideband cooling. We take advantage of the well-resolved excited hyperfine states on the

{D}_{1}

optical transition to produce spin-polarized samples with $1.4\ifmmode\times\else\texttimes\fi{}{10}^{8}$ atoms at temperatures of 1.8 $\ensuremath{\mu}\mathrm{K}$. The phase-space densities are $\ensuremath{\ge}{10}^{\ensuremath{-}4}$, which significantly improves the initial conditions for a subsequent evaporative cooling step. The presented cooling technique using the

{D}_{1}

line can be adapted to other atomic species and is applicable to high-resolution imaging schemes in far off-resonant optical lattices.

A method of sideband Raman cooling to the vibrational ground state of the

m=0

Zeeman sublevel in a far-detuned two-dimensional optical lattice is proposed. In our scheme, the Raman coupling between vibrational manifolds of the adjacent Zeeman sublevels is shifted to the red sideband due to the ac Stark effect induced by a weak pump field. Thus cooling and optical pumping to

m=0

are achieved by purely optical means with coplanar cw laser beams. The optical lattice and cooling parameters are estimated in the framework of simple theoretical models. An application of the transverse sideband cooling method to frequency standards is discussed. Coherent population trapping for the sideband Raman transitions between the degenerate vibrational levels is predicted.