Abstract
We review the development of microwave-frequency standards based on trapped ions. Following two distinct paths, microwave ion clocks have evolved greatly in the last twenty years since the earliest Paul-trap-based units. Laser-cooled ion frequency standards reduce the second-order Doppler shift from ion micromotion and thermal secular motion achieving good signal-to-noise ratios via cycling transitions where as many as ≈ 108 photons per second per ion may be scattered. Today, laser-cooled ion standards are based on linear Paul traps which hold ions near the node line of the trapping electric field, minimizing micromotion at the trapping-field frequency and the consequent second-order Doppler frequency shift. These quadrupole (radial) field traps tightly confine tens of ions to a crystalline single-line structure. As more ions are trapped, space charge forces some ions away from the node-line axis and the second-order Doppler effect grows larger, even at negligibly small secular temperatures. Buffer-gas-cooled clocks rely on large numbers of ions, typically ≈ 107, optically pumped by a discharge lamp at a scattering rate of a few photons per second per ion. To reduce the second-order Doppler shift from space charge repulsion of ions from the trap node line, novel multipole ion traps are now being developed where ions are weakly bound with confining fields that are effectively zero through the trap interior and grow rapidly near the trap electrode “walls”.
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G. J. Dick, R. T. Wang, R. L. Tjoelker: Cryo-cooled sapphire oscillator with ultra-high stability. IEEE Int. Freq. Control Symp. Proc. 52, 528–533 (1998)
D. J. Berkeland, J. D. Miller, J. C. Bergquist, W. M. Itano, D. J. Wineland: Laser-cooled mercury ion frequency standard. Phys. Rev. Lett. 80, 2089–2092 (1998)
R. F. Wuerker, H. Sheldon, R. V. Langmuir: Electrodynamic containment of charged particles. J. Appl. Phys. 30, 342–349 (1959)
H. G. Dehmelt: Radio-frequency spectroscopy of stored ions I: storage. Adv. Atom. Molec. Phys. 3, 53–72 (1969)
P. T.H. Fisk: Trapped-ion and trapped-atom microwave frequency standards. Rep. Prog. Phys. 60(8), 761–818 (1997)
D. J. Berkeland, J. D. Miller, F. C. Cruz, B.C. Young, R. J. Rafac, X. P. Huang, W. M. Itano, J. C. Bergquist, D. J. Wineland: High-resolution, high-accuracy spectroscopy of trapped ions. Atomic Phys. 16, 29–41 (1999)
J. D. Prestage, R. L. Tjoelker, G. J. Dick, L. Maleki: Ultra-stable Hg+ trapped ion frequency standard. J. Mod. Opt. 39, 221–232 (1992)
J. J. Bollinger, D. J. Heinzen, W. M. Itano, S. L. Gilbert, D. J. Wineland: A 303 MHz frequency standard based on trapped Be+ ions. IEEE Trans. Instrum. Meas. 40, 126 (1991)
U. Tanaka, H. Imajo, K. Hayasaks, R. Omukai, M. Watanabe, S. Urabe: Determination of the ground-state hyperfine splitting of trapped 113Cd+ ions. Phys. Rev. A 53, 3982–3985 (1996)
G. J. Dick, C. A. Greenhall: L. O. limited frequency stability for passive atomic frequency standards using square wave frequency modulation. IEEE Int. Freq. Control Symp. Proc. 52, 99–103 (1998)
P. Lemonde, G. Santarelli, P. Laurent, F. P.D. Santos, A. Clairon, C. Salomon: The sensitivity function: a new tool for the evaluation of frequency shifts in atomic spectroscopy. IEEE Int. Freq. Control Symp. Proc. 52, 110–115 (1998)
J. Hoffnagle, R. G. Devoe, L. Reyna, R. G. Brewer: Order-chaos transition of two trapped ions. Phys. Rev. Lett. 61, 255–258 (1988)
R. G. Brewer, J. Hoffnagle, R. G. Devoe, L. Reyna, W. Henshaw: Collision-induced two-ion chaos. Nature 344, 305–309 (1990)
R. Blumel, J. M. Chen, E. Peik, W. Quint, W. Schleich, Y. R. Shen, H. Walther: Phase transitions of stored laser-cooled ions. Nature 334(6180), 309–313 (1988)
R. Blumel, C. Kappler, W. Quint, H. Walther: Chaos and order of laser-cooled ions in a Paul trap. Phys. Rev. A 40, 808–823 (1989)
J. D. Prestage, G. J. Dick, L. Maleki: New ion trap for frequency standard applications. J. Appl. Phys. 66, 1013–1017 (1989)
R. B. Warrington, P. T.H. Fisk, M. J. Wouters, M. A. Lawn, C. Coles: The CSIRO trapped 171Yb+ ion clock: Improved accuracy through laser-cooled operation. Joint EFTF/IEEE Int. Freq. Control Symp. Proc. 53 (1999) in press
J. D. Prestage, R. L. Tjoelker, G. J. Dick, L. Maleki: Improved linear ion trap physics package. IEEE Int. Freq. Control Symp. Proc. 47, 144–147 (1993)
D. Gerlich: Inhomogeneous RF fields: a versatile tool for the study of processes with slow ions. Adv. Chem. Phys. LXXXII, 1–176 (1992)
L. S. Cutler, C. A. Flory, R. P. Giffard, M. D. McGuire: Doppler effects due to thermal macromotion of ions in an rf quadrupole trap. Appl. Phys. B 39, 251–259 (1986)
L. S. Cutler, R. P. Giffard, M. D. McGuire: A trapped mercury-199 ion frequency standard. In: Proc. 13th Annu. PTTI Application and Planning Meeting, NASA Conf. Pub. 2220, 563–578 (1981)
J. D. Prestage, R. L. Tjoelker, L. Maleki: Higher pole linear traps for atomic clock applications. Joint EFTF/IEEE Int. Freq. Control Symp. Proc. 53 (1999) in press
G. R. Janik, J. D. Prestage, L. Maleki: Simple analytic potentials for linear ion traps. J. Appl. Phys. 67, 6050–6055 (1990)
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Prestage, J.D., Tjoelker, R.L., Maleki, L. (2001). Recent Developments in Microwave Ion Clocks. In: Luiten, A.N. (eds) Frequency Measurement and Control. Topics in Applied Physics, vol 79. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-44991-4_8
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DOI: https://doi.org/10.1007/3-540-44991-4_8
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