Mono-Ion Oscillator as Potential Ultimate Laser Frequency Standard

Abstract

An individual atomic ion localized in the center of a small Paul RF quadrupole trap has potential as an ultimate laser frequency standard because, broadly speaking, the ion may be brought to “a state of complete rest in free space” by sideband cooling. As a consequence, all Doppler shifts vanish. “Free Space” is approximated insofar as the electric trapping field vanishes in the center of the trap and there is no Stark effect. Neither need there be a Zeeman effect as magnetic fields may be controlled down to the microgauss range. Naturally, there is no transit time broadening. Minute laser powers provided by harmonic generators suffice for saturation of optical transitions as strongly focused beams may be used. A million-fold atomic amplification of the single-ion fluorescence from a metastable level may bring resolutions of 1 part in 1018 within reach. Copyright © 1982 by The Institute of Electrical and Electronics Engineers, Inc.