201Hg+ co-magnetometer for 199Hg+ trapped ion space atomic clocks

A method for measuring the magnetic field experienced by an atomic clock without significant degradation of clock performance, comprising the steps of:

• providing an atomic clock comprising,
• a linear ion trap that simultaneously traps a first isotope of an element having a resonant microwave transition between two hyperfine energy states, and a second isotope of the same element having a resonant Zeeman transition,
• a first optical source that emits ultraviolet light to optically pump the first isotope ions to a clock transition ground state,
• a second optical source that emits ultraviolet light that optically pumps the second isotope ions to a Zeeman transition ground state,
• a microwave radiation source that simultaneously emits microwave fields resonant with the first isotope's clock transition and the second isotope's Zeeman transition, and
• an optical detector for measuring the fluorescence from optically pumping the first isotopes and the second isotopes;
• emitting ultraviolet light from the first optical source to optically pump the first isotope to the clock transition ground state;
• emitting ultraviolet light from the second optical source to optically pump the second isotope to the Zeeman transition ground state;
• simultaneously emitting microwave fields resonant with the first isotope's clock transition and the second isotope's Zeeman transition to interrogate the clock transition and the Zeeman transition;
• measuring the fluorescence from the optically pumped first and second isotopes using an optical detector;
• and
• determining the magnetic field using the fluorescence measurements.