Laser Cooling and Hyperfine Measurements of Radium-225 Ions

Abstract

${}^{225}$Ra${}^{+}$ ions (nuclear spin $I=1/2$) have transitions that are first-order insensitive to magnetic field noise, which is advantageous for optical clocks and quantum information science. We report on laser cooling and trapping of ${}^{225}$Ra${}^{+}$ ions and hyperfine splitting measurements of the ion's $7s$ ${}^2{\mathrm{S}}_{1/2}$, $7p$ ${}^2{\mathrm{P}}_{1/2}$, and $6d$ ${}^2{\mathrm{D}}_{3/2}$ states. We measured the ground state hyperfine constant, $A({\mathrm{S}}_{1/2})=$ $-27.684511052(5)$ $\mathrm{GHz}$, and the quadratic Zeeman coefficient, $C_2=$ $142.3(1.0)$ ${\mathrm{Hz}\mathrm{G}}^{-2}$, of the ${}^2{\mathrm{S}}_{1/2}(F=0,m_F=0)\leftrightarrow {}^2{\mathrm{S}}_{1/2}(F=1,m_F=0)$ transition. Our result addresses a discrepancy in the literature for the ground state hyperfine splitting. We measured the hyperfine constants of the ${}^2{\mathrm{P}}_{1/2}$ state, $A({\mathrm{P}}_{1/2})=$ $-5.447(4)$ $\mathrm{GHz}$, and the ${}^2{\mathrm{D}}_{3/2}$ state, $A({\mathrm{D}}_{3/2})=$ $-619.7(1.1)$ $\mathrm{MHz}$. We also performed state preparation and measurement using the ground state hyperfine levels and realized a fidelity of $0.9951(9)$.

5 pages, 4 figures

References in corpus (1)

• Laser Cooling and Hyperfine Measurements of Radium-225 Ions

Cited by in corpus (1)

• Laser Cooling and Hyperfine Measurements of Radium-225 Ions