Improvement in medium-long term frequency stability of integrating sphere cold atom clock

摘要

The medium-long term frequency stability of the integrating sphere cold atomclock was improved.During the clock operation, Rb atoms were cooled andmanipulated using cooling light diffusely reflected by the inner surface of amicrowave cavity in the clock. This light heated the cavity and caused afrequency drift from the resonant frequency of the cavity. Power fluctuationsof the cooling light led to atomic density variations in the cavity's centralarea, which increased the clock frequency instability through a cavity pullingeffect. We overcame these limitations with appropriate solutions. A frequencystability of 3.5E-15 was achieved when the integrating time ? increased to 2E4s.