Microwave Atom Chip for Ultracold Trapped Atom Interferometery

We present progress on the development of a microwave atom chip for trapped atom interferometry using spin-specific AC Zeeman (ACZ) potentials. The chip uses three parallel microstrip transmission lines to generate microwave ACZ traps. Efficient DC-10 GHz coupling of microwave signals onto the chip is based on a tapered microstrip wedge interface design, which is supported by simulation and prototype results. We have started micro fabrication of chip components using photolithography and evaporative deposition, including an aluminum nitride-based wedge interface. Furthermore, we are developing multiple microwave amplifier systems to create a microwave lattice, which will enable Ramsey interferometry with spatially separated rubidium-87 spin states. We have also redesigned our potassium laser cooling and trapping system to use fiber amplifiers with improved optical shuttering for more stable production of ultracold atom clouds. This redesign is a first step towards achieving a potassium quantum gases (boson and fermion) for interferometry. This work furthers the development of our precision measurement capabilities for gravimetry and possible measurements of the Casimir-Polder force and submillimeter gravity.