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

摘要

The medium long-term frequency stability of the integrating sphere cold atom clock was improved. During the clock operation, Rb-87 atoms were cooled and manipulated using cooling light diffusely reflected by the inner surface of a microwave cavity in the clock. This light heated the cavity and caused a frequency drift from the resonant frequency of the cavity. Power fluctuations of the cooling light led to atomic density variations in the cavity's central area, which increased the clock frequency instability through the cavity pulling effect. We overcame these limitations with appropriate solutions. A frequency stability of 3.5 x 10(-15) was achieved when the integrating time tau increased to 2 x 10(4) s. (C) 2016 Optical Society of America