Physical Review Applied

Continuous generation of an ultracold atomic beam using crossed moving optical lattices

翔一岡場, Ryoto Takeuchi, Shigenori Tsuji, Hidetoshi Katori

Published Mar 5, 2024• 14 citations

Abstract

Using orthogonally crossed moving lattices, we demonstrate the continuous transport of ${}^{88}\mathrm{Sr}$ atoms in the long-lived metastable ${}^{3}{P}_{0}$ and ${}^{3}{P}_{2}$ states to a region free from scattered laser-cooling light, while two-stage cooling on the ${}^{1}{S}_{0}--{}^{1}{P}_{1}$ and ${}^{3}{P}_{2}--{}^{3}{D}_{3}$ transitions is being conducted. The transfer efficiency between the crossed lattices was close to unity when laser cooling was applied in the crossed region. For a clock laser propagating along the lattice axis, such a lattice-trapped atomic beam enables continuous interrogation of the clock transition free from the Doppler effect arising from the thermal motion of atoms.

DOI: 10.1103/physrevapplied.21.034006

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Physical Review Applied

Continuous generation of an ultracold atomic beam using crossed moving optical lattices

翔一岡場, Ryoto Takeuchi, Shigenori Tsuji, Hidetoshi Katori

Published Mar 5, 2024• 14 citations

Publisher

Abstract

Using orthogonally crossed moving lattices, we demonstrate the continuous transport of

{}^{88}\mathrm{Sr}

atoms in the long-lived metastable

{}^{3}{P}_{0}

and

{}^{3}{P}_{2}

states to a region free from scattered laser-cooling light, while two-stage cooling on the

{}^{1}{S}_{0}--{}^{1}{P}_{1}

and

{}^{3}{P}_{2}--{}^{3}{D}_{3}

transitions is being conducted. The transfer efficiency between the crossed lattices was close to unity when laser cooling was applied in the crossed region. For a clock laser propagating along the lattice axis, such a lattice-trapped atomic beam enables continuous interrogation of the clock transition free from the Doppler effect arising from the thermal motion of atoms.

DOI: 10.1103/physrevapplied.21.034006

Related papers

Continuous outcoupling of ultracold strontium atoms combining three different traps

Ryoto Takeuchi, Hayaki Chiba, 翔一岡場 +3 more

Abstract We have demonstrated the continuous outcoupling of ultracold 88 Sr atoms using a moving optical lattice. While Sr atoms are Zeeman-slowed and magneto-optically trapped on the 1 S 0 – 1 P 1 transition, the atoms relaxed to the 5s5p 3 P 2 metastable state are magnetically trapped and Doppler cooled on the 5s5p 3 P 2 –5s4d 3 D 3 transition at 2.92 μ m. By optically pumping the atoms to the 5s5p 3 P 0 state, we outcouple the atoms by a moving optical lattice. Such a continuous atomic source enables superradiant lasers and the zero-dead-time operation of atom interferometers and optical lattice clocks.Abstract We have demonstrated the continuous outcoupling of ultracold 88 Sr atoms using a moving optical lattice. While Sr atoms are Zeeman-slowed and magneto-optically trapped on the 1 S 0 – 1 P 1 transition, the atoms relaxed to the 5s5p 3 P 2 metastable state are magnetically trapped and Doppler cooled on the 5s5p 3 P 2 –5s4d 3 D 3 transition at 2.92 μ m. By optically pumping the atoms to the 5s5p 3 P 0 state, we outcouple the atoms by a moving optical lattice. Such a continuous atomic source enables superradiant lasers and the zero-dead-time operation of atom interferometers and optical lattice clocks.

Applied Physics ExpressApr 1, 202316 citations

Narrow-line-mediated Sisyphus cooling in the $^{3}\mathrm{P}_{2}$ metastable state of strontiumNarrow-line-mediated Sisyphus cooling in the $^{3}\mathrm{P}_{2}$ metastable state of strontium

Chun-Chia Chen, Ryoto Takeuchi, 翔一岡場 +1 more

We demonstrate narrow-line-mediated Sisyphus cooling of magnetically trapped strontium (Sr) in the $5s5p\,^{3}\textrm{P}_{2}$ state. A 641 nm standing-wave, blue-detuned from the $5s4d\,^{3}\textrm{D}_{3}$ $\,\rightarrow$ $\,5p4d\,^{3}\textrm{F}_{4}$ transition, creates a dissipative optical lattice in the $^{3}\textrm{D}_{3}$ state. By combining Doppler cooling and Sisyphus cooling on the $5s5p\,^{3}\textrm{P}_{2}$ $\,\rightarrow$ $5s4d\,^{3}\textrm{D}_{3}$ transition at 2.92 $μ$ m, we observed efficient cooling of magnetically trapped atoms. By optically pumping the atoms to the $5s5p\,^{3}\textrm{P}_{0}$ state, we facilitate continuous outcoupling via a moving optical lattice with two fold improvement in atom number. Our scheme applies to next-generation quantum sensors using continuous ultracold atomic beams.We demonstrate narrow-line-mediated Sisyphus cooling of magnetically trapped strontium (Sr) in the $5s5p\,^{3}\textrm{P}_{2}$ state. A 641 nm standing-wave, blue-detuned from the $5s4d\,^{3}\textrm{D}_{3}$$\,\rightarrow$ $\,5p4d\,^{3}\textrm{F}_{4}$ transition, creates a dissipative optical lattice in the $^{3}\textrm{D}_{3}$ state. By combining Doppler cooling and Sisyphus cooling on the $5s5p\,^{3}\textrm{P}_{2}$$\,\rightarrow$ $5s4d\,^{3}\textrm{D}_{3}$ transition at 2.92 $μ$m, we observed efficient cooling of magnetically trapped atoms. By optically pumping the atoms to the $5s5p\,^{3}\textrm{P}_{0}$ state, we facilitate continuous outcoupling via a moving optical lattice with two fold improvement in atom number. Our scheme applies to next-generation quantum sensors using continuous ultracold atomic beams.

arXiv:2506.19701Jun 24, 20250 citations

Three-stage laser cooling of Sr atoms using the 5s5pP23 metastable state below Doppler temperatures

Tomoya Akatsuka, Koji Hashiguchi, Tadahiro TAKAHASHI +3 more

We report three-stage laser cooling of Sr atoms using the $5{s}^{2}\phantom{\rule{0.16em}{0ex}}^{1}S_{0}$ ground state and the $5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}$ metastable state. $^{87}\mathrm{Sr}$ atoms are precooled in a magneto-optical trap simultaneously operated on the $5{s}^{2}\phantom{\rule{0.16em}{0ex}}^{1}S_{0}$ -- $5s5p\phantom{\rule{0.16em}{0ex}}^{1}P_{1}$ transition at 461 nm and on the $5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}$ -- $5s5d\phantom{\rule{0.16em}{0ex}}^{3}D_{3}$ transition at 496 nm. Atoms optically pumped to the $5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}(F=13/2)$ state are magneto-optically trapped and cooled down to 2.5(2) $\ensuremath{\mu}\mathrm{K}$ on the $5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}$ -- $5s4d\phantom{\rule{0.16em}{0ex}}^{3}D_{3}$ transition at $2.9\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$. Using this transition, we investigate one dimensional polarization gradient cooling of $^{88}\mathrm{Sr}$ atoms, which have simple energy levels without hyperfine structure, down to 0.22(18) $\ensuremath{\mu}\mathrm{K}$ or 17 times the recoil temperature. We discuss prospects for continuous generation of ultracold Sr atoms combined with a state transfer technique.We report three-stage laser cooling of Sr atoms using the $5{s}^{2}\phantom{\rule{0.16em}{0ex}}^{1}S_{0}$ ground state and the $5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}$ metastable state. $^{87}\mathrm{Sr}$ atoms are precooled in a magneto-optical trap simultaneously operated on the $5{s}^{2}\phantom{\rule{0.16em}{0ex}}^{1}S_{0}$--$5s5p\phantom{\rule{0.16em}{0ex}}^{1}P_{1}$ transition at 461 nm and on the $5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}$--$5s5d\phantom{\rule{0.16em}{0ex}}^{3}D_{3}$ transition at 496 nm. Atoms optically pumped to the $5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}(F=13/2)$ state are magneto-optically trapped and cooled down to 2.5(2) $\ensuremath{\mu}\mathrm{K}$ on the $5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}$--$5s4d\phantom{\rule{0.16em}{0ex}}^{3}D_{3}$ transition at $2.9\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$. Using this transition, we investigate one dimensional polarization gradient cooling of $^{88}\mathrm{Sr}$ atoms, which have simple energy levels without hyperfine structure, down to 0.22(18) $\ensuremath{\mu}\mathrm{K}$ or 17 times the recoil temperature. We discuss prospects for continuous generation of ultracold Sr atoms combined with a state transfer technique.

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Ultracold 88Sr atoms for an optical lattice clock

Thomas Legero, J. S. Raaj Vellore Winfred, F. Riehle +1 more

This paper reports results of cooling and trapping of88Sr for future use in an optical lattice clock. Strontium atoms are cooled to ultra-cold temperatures using a two-stage cooling process. In the first stage, atoms are captured from a Zeeman-slowed atomic beam and cooled to 2 mK in a magneto optical trap operated on the1So-1P1transition at 461 nm. The second cooling stage utilizes the spin forbidden1So-3P1transition at 689 nm. To reach ultra-cold temperatures, 50 ms of broadband cooling is followed by 28 ms long single frequency cooling. The transfer efficiency from the first to the second cooling stage was measured to be 23%, leaving 7 x 106 atoms at a temperature of 1 muK. The atomic cloud is overlapped with a horizontally oriented 1-D far-off resonance optical dipole trap (FORT) at 813 nm with an effective potential depth of 25 muK. Due to equal light shifts of the1Soand the3P1state simultaneous Doppler cooling during the atom loading into the FORT is possible which leads to a transfer efficiency into the dipole trap of up to 60%.This paper reports results of cooling and trapping of88Sr for future use in an optical lattice clock. Strontium atoms are cooled to ultra-cold temperatures using a two-stage cooling process. In the first stage, atoms are captured from a Zeeman-slowed atomic beam and cooled to 2 mK in a magneto optical trap operated on the1So-1P1transition at 461 nm. The second cooling stage utilizes the spin forbidden1So-3P1transition at 689 nm. To reach ultra-cold temperatures, 50 ms of broadband cooling is followed by 28 ms long single frequency cooling. The transfer efficiency from the first to the second cooling stage was measured to be 23%, leaving 7 x 106 atoms at a temperature of 1 muK. The atomic cloud is overlapped with a horizontally oriented 1-D far-off resonance optical dipole trap (FORT) at 813 nm with an effective potential depth of 25 muK. Due to equal light shifts of the1Soand the3P1state simultaneous Doppler cooling during the atom loading into the FORT is possible which leads to a transfer efficiency into the dipole trap of up to 60%.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)May 1, 20074 citations

Midinfrared magneto-optical trap of metastable strontium for an optical lattice clock

Richard Hobson, William Bowden, Alvise Vianello +2 more

We report on the realization of a magneto-optical trap (MOT) for metastable strontium operating on the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition between the energy levels $5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{2}$ and $5s4d{\phantom{\rule{0.16em}{0ex}}}^{3}{D}_{3}$ . The strontium atoms are initially captured in a MOT operating on the 461-nm transition between the energy levels $5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}$ and $5s5p{\phantom{\rule{0.16em}{0ex}}}^{1}{P}_{1}$ , prior to being transferred into the metastable MOT and cooled to a final temperature of 6 $\ensuremath{\mu}\mathrm{K}$. Challenges arising from aligning the midinfrared and 461-nm light are mitigated by employing the same pyramid reflector to realize both MOTs. Finally, the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition is used to realize a full cooling sequence for an optical lattice clock, in which cold samples of $^{87}\mathrm{Sr}$ are loaded into a magic-wavelength optical lattice and initialized in a spin-polarized state to allow high-precision spectroscopy of the $5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}$ to $5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{0}$ clock transition.We report on the realization of a magneto-optical trap (MOT) for metastable strontium operating on the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition between the energy levels $5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{2}$ and $5s4d{\phantom{\rule{0.16em}{0ex}}}^{3}{D}_{3}$. The strontium atoms are initially captured in a MOT operating on the 461-nm transition between the energy levels $5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}$ and $5s5p{\phantom{\rule{0.16em}{0ex}}}^{1}{P}_{1}$, prior to being transferred into the metastable MOT and cooled to a final temperature of 6 $\ensuremath{\mu}\mathrm{K}$. Challenges arising from aligning the midinfrared and 461-nm light are mitigated by employing the same pyramid reflector to realize both MOTs. Finally, the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition is used to realize a full cooling sequence for an optical lattice clock, in which cold samples of $^{87}\mathrm{Sr}$ are loaded into a magic-wavelength optical lattice and initialized in a spin-polarized state to allow high-precision spectroscopy of the $5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}$ to $5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{0}$ clock transition.

arXiv:2001.05210Physical Review AJan 14, 202023 citations

Lattice-induced photon scattering in an optical lattice clock

Sören Dörscher, R. Schwarz, Ali Al-Masoudi +3 more

Off-resonant scattering of lattice laser radiation by ${}^{87}$ Sr atoms in the two states ${}^{1}{S}_{0}$ and ${}^{3}{P}_{0}$ and its effect on clock operation are investigated. It is found that Raman scattering eventually limits the achievable frequency instability and thus limits the useful interrogation time in optical lattice clocks at presently used lattice depths.Off-resonant scattering of lattice laser radiation by ${}^{87}$Sr atoms in the two states ${}^{1}{S}_{0}$ and ${}^{3}{P}_{0}$ and its effect on clock operation are investigated. It is found that Raman scattering eventually limits the achievable frequency instability and thus limits the useful interrogation time in optical lattice clocks at presently used lattice depths.

arXiv:1802.02945Physical Review AJun 25, 201859 citations

Using orthogonally crossed moving lattices, we demonstrate the continuous transport of

{}^{88}\mathrm{Sr}

atoms in the long-lived metastable

{}^{3}{P}_{0}

and

{}^{3}{P}_{2}

states to a region free from scattered laser-cooling light, while two-stage cooling on the

{}^{1}{S}_{0}--{}^{1}{P}_{1}

and

{}^{3}{P}_{2}--{}^{3}{D}_{3}

Narrow-line-mediated Sisyphus cooling in the

^{3}\mathrm{P}_{2}

metastable state of strontium

We demonstrate narrow-line-mediated Sisyphus cooling of magnetically trapped strontium (Sr) in the

5s5p\,^{3}\textrm{P}_{2}

state. A 641 nm standing-wave, blue-detuned from the

5s4d\,^{3}\textrm{D}_{3}

\,\rightarrow

\,5p4d\,^{3}\textrm{F}_{4}

transition, creates a dissipative optical lattice in the

^{3}\textrm{D}_{3}

state. By combining Doppler cooling and Sisyphus cooling on the

5s5p\,^{3}\textrm{P}_{2}

\,\rightarrow

5s4d\,^{3}\textrm{D}_{3}

transition at 2.92

μ

m, we observed efficient cooling of magnetically trapped atoms. By optically pumping the atoms to the

5s5p\,^{3}\textrm{P}_{0}

state, we facilitate continuous outcoupling via a moving optical lattice with two fold improvement in atom number. Our scheme applies to next-generation quantum sensors using continuous ultracold atomic beams.

We report three-stage laser cooling of Sr atoms using the

5{s}^{2}\phantom{\rule{0.16em}{0ex}}^{1}S_{0}

ground state and the

5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}

metastable state.

^{87}\mathrm{Sr}

atoms are precooled in a magneto-optical trap simultaneously operated on the

5{s}^{2}\phantom{\rule{0.16em}{0ex}}^{1}S_{0}

5s5p\phantom{\rule{0.16em}{0ex}}^{1}P_{1}

transition at 461 nm and on the

5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}

5s5d\phantom{\rule{0.16em}{0ex}}^{3}D_{3}

transition at 496 nm. Atoms optically pumped to the

5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}(F=13/2)

state are magneto-optically trapped and cooled down to 2.5(2) $\ensuremath{\mu}\mathrm{K}$ on the

5s5p\phantom{\rule{0.16em}{0ex}}^{3}P_{2}

5s4d\phantom{\rule{0.16em}{0ex}}^{3}D_{3}

transition at $2.9\phantom{\rule{0.28em}{0ex}}\ensuremath{\mu}\mathrm{m}$. Using this transition, we investigate one dimensional polarization gradient cooling of

^{88}\mathrm{Sr}

atoms, which have simple energy levels without hyperfine structure, down to 0.22(18) $\ensuremath{\mu}\mathrm{K}$ or 17 times the recoil temperature. We discuss prospects for continuous generation of ultracold Sr atoms combined with a state transfer technique.

We report on the realization of a magneto-optical trap (MOT) for metastable strontium operating on the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition between the energy levels

5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{2}

and

5s4d{\phantom{\rule{0.16em}{0ex}}}^{3}{D}_{3}

. The strontium atoms are initially captured in a MOT operating on the 461-nm transition between the energy levels

5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}

and

5s5p{\phantom{\rule{0.16em}{0ex}}}^{1}{P}_{1}

, prior to being transferred into the metastable MOT and cooled to a final temperature of 6 $\ensuremath{\mu}\mathrm{K}$. Challenges arising from aligning the midinfrared and 461-nm light are mitigated by employing the same pyramid reflector to realize both MOTs. Finally, the 2.92-$\ensuremath{\mu}\mathrm{m}$ transition is used to realize a full cooling sequence for an optical lattice clock, in which cold samples of

^{87}\mathrm{Sr}

are loaded into a magic-wavelength optical lattice and initialized in a spin-polarized state to allow high-precision spectroscopy of the

5{s}^{2}{\phantom{\rule{0.16em}{0ex}}}^{1}{S}_{0}

5s5p{\phantom{\rule{0.16em}{0ex}}}^{3}{P}_{0}

clock transition.

Off-resonant scattering of lattice laser radiation by

{}^{87}

Sr atoms in the two states

{}^{1}{S}_{0}

and

{}^{3}{P}_{0}

and its effect on clock operation are investigated. It is found that Raman scattering eventually limits the achievable frequency instability and thus limits the useful interrogation time in optical lattice clocks at presently used lattice depths.