arXiv:1910.06351 · Physical Review A

Measurements of electric quadrupole transition frequencies in Ra+226

C. A. Holliman, Mingyu Fan, Andrew M. Jayich

Published Dec 19, 2019• 9 citations

Abstract

We report the first driving of the $7s{\phantom{\rule{0.16em}{0ex}}}^{2}{S}_{1/2}\ensuremath{\rightarrow}6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{3/2}$ and $7s{\phantom{\rule{0.16em}{0ex}}}^{2}{S}_{1/2}\ensuremath{\rightarrow}6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{5/2}$ electric quadrupole (E2) transitions in ${\mathrm{Ra}}^{+}$. We measure the frequencies of both E2 transitions and two other low-lying transitions in $^{226}\mathrm{Ra}^{+}$ that are important for controlling the radium ion's motional and internal states: $6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{3/2}\ensuremath{\rightarrow}7p{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}^{o}$ and $6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{5/2}\ensuremath{\rightarrow}7p{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}^{o}$.

DOI: 10.1103/physreva.100.062512

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arXiv:1910.06351 · Physical Review A

Measurements of electric quadrupole transition frequencies in Ra+226

C. A. Holliman, Mingyu Fan, Andrew M. Jayich

Published Dec 19, 2019• 9 citations

arXiv HTML PDF

Abstract

We report the first driving of the

7s{\phantom{\rule{0.16em}{0ex}}}^{2}{S}_{1/2}\ensuremath{\rightarrow}6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{3/2}

and

7s{\phantom{\rule{0.16em}{0ex}}}^{2}{S}_{1/2}\ensuremath{\rightarrow}6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{5/2}

electric quadrupole (E2) transitions in

{\mathrm{Ra}}^{+}

. We measure the frequencies of both E2 transitions and two other low-lying transitions in

^{226}\mathrm{Ra}^{+}

that are important for controlling the radium ion's motional and internal states:

6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{3/2}\ensuremath{\rightarrow}7p{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}^{o}

and

6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{5/2}\ensuremath{\rightarrow}7p{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}^{o}

DOI: 10.1103/physreva.100.062512

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We report the first operation of a ${\mathrm{Ra}}^{+}$ optical clock, a promising high-performance clock candidate. The clock uses a single trapped $^{226}{\mathrm{Ra}}^{+}$ ion and operates on the $7s\text{ }^{2}{S}_{1/2}\ensuremath{\rightarrow}6d\text{ }^{2}{D}_{5/2}$ electric quadrupole transition. By self-referencing three pairs of symmetric Zeeman transitions, we demonstrate a frequency instability of $1.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}/\sqrt{\ensuremath{\tau}}$, where $\ensuremath{\tau}$ is the averaging time in seconds. The total systematic uncertainty is evaluated to be $\mathrm{\ensuremath{\Delta}}\ensuremath{\nu}/\ensuremath{\nu}=9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$. Using the clock, we realize the first measurement of the ratio of the ${D}_{5/2}$ state to the ${S}_{1/2}$ state Land\'e $g$ -factors: ${g}_{D}/{g}_{S}=0.598\text{ }805\text{ }3(11)$ . A ${\mathrm{Ra}}^{+}$ optical clock could improve limits on the time variation of the fine structure constant, $\stackrel{\ifmmode \dot{}\else \textperiodcentered \fi{}}{\ensuremath{\alpha}}/\ensuremath{\alpha}$, in an optical frequency comparison. The ion also has several features that make it a suitable system for a transportable optical clock.We report the first operation of a ${\mathrm{Ra}}^{+}$ optical clock, a promising high-performance clock candidate. The clock uses a single trapped $^{226}{\mathrm{Ra}}^{+}$ ion and operates on the $7s\text{ }^{2}{S}_{1/2}\ensuremath{\rightarrow}6d\text{ }^{2}{D}_{5/2}$ electric quadrupole transition. By self-referencing three pairs of symmetric Zeeman transitions, we demonstrate a frequency instability of $1.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}/\sqrt{\ensuremath{\tau}}$, where $\ensuremath{\tau}$ is the averaging time in seconds. The total systematic uncertainty is evaluated to be $\mathrm{\ensuremath{\Delta}}\ensuremath{\nu}/\ensuremath{\nu}=9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$. Using the clock, we realize the first measurement of the ratio of the ${D}_{5/2}$ state to the ${S}_{1/2}$ state Land\'e $g$-factors: ${g}_{D}/{g}_{S}=0.598\text{ }805\text{ }3(11)$. A ${\mathrm{Ra}}^{+}$ optical clock could improve limits on the time variation of the fine structure constant, $\stackrel{\ifmmode \dot{}\else \textperiodcentered \fi{}}{\ensuremath{\alpha}}/\ensuremath{\alpha}$, in an optical frequency comparison. The ion also has several features that make it a suitable system for a transportable optical clock.

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Coherent excitation of the 6S1/2 to 5D3/2 electric-quadrupole transition in 138 Ba +

Adam Kleczewski, Matthew Hoffman, Jeff A. Sherman +3 more

The electric dipole-forbidden, quadrupole $6{S}_{1/2}\ensuremath{\leftrightarrow}5{D}_{3/2}$ transition in Ba ${}^{+}$ near 2051 nm, with a natural linewidth of 13 mHz, is attractive for potential observation of parity nonconservation, and also as a clock transition for a barium ion optical frequency standard. This transition also offers a direct means of populating the metastable $5{D}_{3/2}$ state to measure the nuclear magnetic octupole moment in the odd barium isotopes. Light from a diode-pumped, solid-state Tm,Ho:YLF laser operating at 2051 nm is used to coherently drive this transition between resolved Zeeman levels in a single trapped ${}^{138}$ Ba ${}^{+}$ ion. The frequency of the laser is stabilized to a high-finesse Fabry-P\'erot cavity at 1025 nm after being frequency doubled. Rabi oscillations on this transition indicate a laser-ion coherence time of 3 ms, most likely limited by ambient magnetic field fluctuations.The electric dipole-forbidden, quadrupole $6{S}_{1/2}\ensuremath{\leftrightarrow}5{D}_{3/2}$ transition in Ba${}^{+}$ near 2051 nm, with a natural linewidth of 13 mHz, is attractive for potential observation of parity nonconservation, and also as a clock transition for a barium ion optical frequency standard. This transition also offers a direct means of populating the metastable $5{D}_{3/2}$ state to measure the nuclear magnetic octupole moment in the odd barium isotopes. Light from a diode-pumped, solid-state Tm,Ho:YLF laser operating at 2051 nm is used to coherently drive this transition between resolved Zeeman levels in a single trapped ${}^{138}$Ba${}^{+}$ ion. The frequency of the laser is stabilized to a high-finesse Fabry-P\'erot cavity at 1025 nm after being frequency doubled. Rabi oscillations on this transition indicate a laser-ion coherence time of 3 ms, most likely limited by ambient magnetic field fluctuations.

arXiv:1203.1978Physical Review AApr 20, 201214 citations

We report the first driving of the

7s{\phantom{\rule{0.16em}{0ex}}}^{2}{S}_{1/2}\ensuremath{\rightarrow}6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{3/2}

and

7s{\phantom{\rule{0.16em}{0ex}}}^{2}{S}_{1/2}\ensuremath{\rightarrow}6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{5/2}

electric quadrupole (E2) transitions in

{\mathrm{Ra}}^{+}

. We measure the frequencies of both E2 transitions and two other low-lying transitions in

^{226}\mathrm{Ra}^{+}

that are important for controlling the radium ion's motional and internal states:

6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{3/2}\ensuremath{\rightarrow}7p{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}^{o}

and

6d{\phantom{\rule{0.16em}{0ex}}}^{2}{D}_{5/2}\ensuremath{\rightarrow}7p{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}^{o}

We report on spectroscopy of the low-lying electronic transitions in

^{224}\mathrm{Ra}^{+}

. We measured the frequencies of the $^{2}S_{1/2}\ensuremath{\leftrightarrow}^{2}P_{1/2}$ cooling transition, the $^{2}S_{1/2}\ensuremath{\leftrightarrow}^{2}D_{5/2}$ clock transition, the $^{2}D_{3/2}\ensuremath{\leftrightarrow}^{2}P_{3/2}$ electric dipole transition, and the $^{2}D_{5/2}\ensuremath{\leftrightarrow}^{2}P_{3/2}$ cleanout transition. From these measurements we calculate the frequencies of the $^{2}D_{3/2}\ensuremath{\leftrightarrow}^{2}P_{1/2}$ repump transition, the $^{2}S_{1/2}\ensuremath{\leftrightarrow}^{2}D_{3/2}$ electric quadrupole transition, and the $^{2}S_{1/2}\ensuremath{\leftrightarrow}^{2}P_{3/2}$ electric dipole transition. The ion's low charge-to-mass ratio and convenient wavelengths make

{}^{224}{\mathrm{Ra}}^{+}

a promising optical clock candidate.

We report a measurement of the radium ion's

7p\phantom{\rule{0.16em}{0ex}}^{2}P_{3/2}

state branching fractions and improved theoretical calculations. With a single laser-cooled

{}^{226}{\mathrm{Ra}}^{+}

ion we measure the

{P}_{3/2}

branching fractions to the

7s\phantom{\rule{0.16em}{0ex}}^{2}S_{1/2}

ground state

0.876\phantom{\rule{0.16em}{0ex}}78(20)

, the

6d\phantom{\rule{0.16em}{0ex}}^{2}D_{5/2}

state

0.107\phantom{\rule{0.16em}{0ex}}59(10)

, and the

6d\phantom{\rule{0.16em}{0ex}}^{2}D_{3/2}

state

0.015\phantom{\rule{0.16em}{0ex}}63(21)

We explore the potential of the electric quadrupole transitions

7s {}^{2}{S}_{1/2}

6d {}^{2}{D}_{3/2}

6d {}^{2}{D}_{5/2}

in radium isotopes as single-ion optical frequency standards. The frequency shifts of the clock transitions due to external fields and the corresponding uncertainties are calculated. Several competitive

{}^{A}

{}^{+}

candidates, with

A=

223--229, are identified. In particular, we show that the transition

7s {}^{2}{S}_{1/2} (F=2,{m}_{F}=0)

6d {}^{2}{D}_{3/2} (F=0,{m}_{F}=0)

at 828 nm in

^{223}\mathrm{Ra}

{}^{+}

, with no linear Zeeman and electric quadrupole shifts, stands out as a relatively simple case, which could be exploited as a compact, robust, and low-cost atomic clock operating at a fractional frequency uncertainty of ${10}^{\ensuremath{-}17}$. With more experimental effort, the

^{223,225,226}\mathrm{Ra}

{}^{+}

clocks could be pushed to a projected performance reaching the ${10}^{\ensuremath{-}18}$ level.

We report the first operation of a

{\mathrm{Ra}}^{+}

optical clock, a promising high-performance clock candidate. The clock uses a single trapped

^{226}{\mathrm{Ra}}^{+}

ion and operates on the $7s\text{ }^{2}{S}_{1/2}\ensuremath{\rightarrow}6d\text{ }^{2}{D}_{5/2}$ electric quadrupole transition. By self-referencing three pairs of symmetric Zeeman transitions, we demonstrate a frequency instability of $1.1\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}13}/\sqrt{\ensuremath{\tau}}$, where $\ensuremath{\tau}$ is the averaging time in seconds. The total systematic uncertainty is evaluated to be $\mathrm{\ensuremath{\Delta}}\ensuremath{\nu}/\ensuremath{\nu}=9\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}16}$. Using the clock, we realize the first measurement of the ratio of the

{D}_{5/2}

state to the

{S}_{1/2}

state Land\'e

g

-factors:

{g}_{D}/{g}_{S}=0.598\text{ }805\text{ }3(11)

. A

{\mathrm{Ra}}^{+}

optical clock could improve limits on the time variation of the fine structure constant, $\stackrel{\ifmmode \dot{}\else \textperiodcentered \fi{}}{\ensuremath{\alpha}}/\ensuremath{\alpha}$, in an optical frequency comparison. The ion also has several features that make it a suitable system for a transportable optical clock.

We explore the potential of the electric quadrupole transitions

7s\,^2S_{1/2}

6d\,^2D_{3/2}

6d\,^2D_{5/2}

^A

^+

candidates with

A=

223 - 229 are identified. In particular, we show that the transition

7s\,^2S_{1/2}\,(F=2,m_F=0)

6d\,^2D_{3/2}\,(F=0,m_F=0)

at 828 nm in

^{223}

^+

10^{-17}

. With more experimental effort, the

^{223,225,226}

^+

clocks could be pushed to a projected performance reaching the

10^{-18}

level.

The electric dipole-forbidden, quadrupole $6{S}_{1/2}\ensuremath{\leftrightarrow}5{D}_{3/2}$ transition in Ba

{}^{+}

near 2051 nm, with a natural linewidth of 13 mHz, is attractive for potential observation of parity nonconservation, and also as a clock transition for a barium ion optical frequency standard. This transition also offers a direct means of populating the metastable

5{D}_{3/2}

state to measure the nuclear magnetic octupole moment in the odd barium isotopes. Light from a diode-pumped, solid-state Tm,Ho:YLF laser operating at 2051 nm is used to coherently drive this transition between resolved Zeeman levels in a single trapped

{}^{138}

{}^{+}

ion. The frequency of the laser is stabilized to a high-finesse Fabry-P\'erot cavity at 1025 nm after being frequency doubled. Rabi oscillations on this transition indicate a laser-ion coherence time of 3 ms, most likely limited by ambient magnetic field fluctuations.