A compact atom-chip apparatus for Sagnac interferometry

Sagnac interferometers using trapped atoms offer several potential advantages for rotation sensing, since it is possible to achieve long measurement times and large enclosed areas without requiring a large free-fall distance. We describe a new compact apparatus suitable for Sagnac measurements, which uses an atom chip to achieve rapid condensate production and a stable magnetic trap for interferometry. To our knowledge, this is the first implementation of a time-orbiting potential (TOP) trap using an atom chip. The ac fields of a TOP trap reduce the interferometer’s sensitivity to stray environmental fields. However, the fields can induce eddy currents in the chip, which must be controlled. The atom chip is based on direct-bonded copper on aluminum nitride, which provides excellent thermal and mechanical properties. The chip will be integrated into a novel vapor cell architecture that provides the required optical access as well as a long vacuum lifetime.  We will describe the apparatus performance and recent interferometry results.