A new trapped ion atomic clock based on 201Hg

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 57; no. 3; pp. 629 - 635
• Main Authors: Burt, E.A., Taghavi-Larigani, S., Tjoelker, R.L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.03.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Atomic clocks; Charge carrier processes; Clocks & watches; Exact sciences and technology; Fluctuations; Isotopes; Local oscillators; Magnetic field measurement; Magnetic fields; Magnetic shielding; Measurements common to several branches of physics and astronomy; Mercury (metals); Metrology, measurements and laboratory procedures; Optical pumping; Physics; Spectroscopy; Spectrum analysis; Time and frequency; Non linear oscillator; Aliasing; Far field; Time delay; Impact noise; Doppler effect; Magnetic transitions; Mercury; Local effect; High-resolution methods; Atomic clocks; Magnetic measurement
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2010.1458

High-resolution spectroscopy has been performed on the ground-state hyperfine transitions in trapped 201 Hg + ions as part of a program to investigate the viability of 201 Hg + for clock applications. Part of the spectroscopy work was directed at magnetic-field-sensitive hyperfine lines with ¿m F =0, which allow accurate Doppler-free measurement of the magnetic field experienced by the trapped ions. Although it is possible to measure Doppler-free magnetic-field-sensitive transitions in the commonly used clock isotope, 199 Hg + , it is more difficult. In this paper, we discuss how this 201 Hg + feature may be exploited to produce a more stable clock or one requiring less magnetic shielding in environments with magnetic field fluctuations far in excess of what is normally found in the laboratory. We have also determined that in discharge-lamp-based trapped mercury ion clocks, the optical pumping time for 201 Hg + is about 3 times shorter than that of 199 Hg + This can be used to reduce dead time in the interrogation cycle for these types of clocks, thereby reducing the impact of local oscillator noise aliasing effects.