Towards a Microwave-Laser Double Resonance Passive Frequency Standard Using Trapped Ytterbium Ions.

S. Mulholland, H. A. Klein, G. P. Barwood +6 more

Fisk, P.T.H., M.A. Lawn, C. Coles +2 more

Heather L. Partner

Peter D. D. Schwindt

A microfabricated ion frequency standard (i.e. an ion clock) is disclosed with a permanently-sealed vacuum package containing a source of ytterbium (Yb) ions and an octupole ion trap. The source of Yb ions is a micro-hotplate which generates Yb atoms which are then ionized by a ultraviolet light-emitting diode or a field-emission electron source. The octupole ion trap, which confines the Yb ions, is formed from suspended electrodes on a number of stacked-up substrates. A microwave source excites a ground-state transition frequency of the Yb ions, with a frequency-doubled vertical-external-cavity laser (VECSEL) then exciting the Yb ions up to an excited state to produce fluorescent light which is used to tune the microwave source to the ground-state transition frequency, with the microwave source providing a precise frequency output for the ion clock.

Peter Fisk, Matthew J. Sellars, M.A. Lawn +1 more

D.J. Siedel, A. Williams, R. W. Berends +1 more

A ytterbium ion standard currently under development for both ground and space applications is described. The ytterbium ion was chosen for its large hyperfine splitting at 12.6 GHz and the accessibility of its first excited electronic energy levels with light from frequency-doubled semiconductor and solid state lasers. The desired characteristics of a spaceborne instrument and the choice of ytterbium are discussed. The results of spectroscopy carried out on trapped ytterbium ions to determine means for overcoming the population trapping difficulties associated with this ion are presented.>