Introduction to Optical Cavities, Atomic Clocks, Cold Atoms and Gravitational Waves

Jia Zhang, Xiaolei Guan, Xun Gao +3 more

The cavity-pulling suppression advantage of active optical clocks (AOCs) helps to realize atomic clocks with superior performance. However, realization of continuous-wave cold-atom AOCs is a highly challenging task. In this work, we proposed an AOC scheme with diffuse-laser-cooled atoms. Combining the advantages of diffuse laser cooling to easily prepare cold-atom cloud with large volume on the scale of meters and the four-level structure to greatly reduce the light shift, it is expected to realize the continuous output of AOC superradiant signals. We experimentally realized a 100-cm-long cold87Rb atom cloud as the gain medium. The 1367 nm AOC superradiant signal with a power of 0.3$\mu \mathrm{W}$has been achieved without resonant cavity feedback. In the future, we will continue to advance the experiment and also conduct research on 420 nm blue light cooling.

Andreas Wicht, K. Danzmann, Michael Fleischhauer +3 more

Jun Ye, T. W. Lynn

Yu Wang

We review the field of cold atom physics and its applications in a microgravity environment,including atomic clocks in space,atomic interferometers,ultra-cold atom physics,and the proposed investigation of general relativity.A brief introduction is presented of the research in the Shanghai Institute of Optics and Fine Mechanics on atomic clocks in space,Bose-Einstein condensation and atom chips in a microgravity environment.

Aldo Godone, Salvatore Micalizio

We report on a theoretical analysis of the phase-shift in compact atomic clocks working either with cold or thermal atoms. It is well known that in a microwave cavity with electromagnetic losses, a traveling wave adds to the standing wave of a given resonant mode. We calculate the spatial varying phase related to this travelling wave for two geometries of interest in clock applications, the cylindrical cavity and the spherical cavity. Due to their motion, the atoms probe different regions of the cavity and then experience different phases of the interrogating microwave field. We show that this combination of atomic motion and spatial changing phase results in a phase-shift of the clock frequency, well known in primary frequency standards, that can affect the metrological performances also of vapor cell and compact cold-atom clocks. In the latter case, we evaluate the phase-shift for a space clock and a ground clock.

C. A. Schrama, Dirk Bouwmeester, Gerard Nienhuis +1 more