Patent ID: 6888780

Claim:
A method for operating an atomic clock comprising the steps of: a. optically pumping atoms into a ground-state sublevel of maximum or minimum spin from which end resonances can be excited; b. simultaneously exciting a microwave end resonance and a Zeeman end resonance from a same end state of the atoms either by: pumping the atoms with constant-intensity, circularly-polarized optical pumping light and applying two alternating magnetic fields, one of the alternating magnetic fields oscillating at a microwave frequency of the microwave end resonance and the other of the alternating magnetic fields oscillating at a radio frequency of the Zeeman end resonance, or pumping the atoms with modulated circularly-polarized optical pumping light simultaneously modulated at the frequency of the microwave end resonance and at the frequency of the Zeeman end resonance to produce coherent population trapping resonances; and c. detecting that the microwave end resonance and Zeeman end resonance have been excited.