Portable Yb Optical Lattice Clock: Towards Precision Measurement Outside the Lab

As optical atomic clocks continue to increase in precision, interest has grown in redefining the SI second based on an optical atomic transition. Before the second can be redefined, a wide range of optical clock comparisons must be made to rigorously test the realizable performance. Due to challenges in long-distance optical time and frequency transfer, these comparisons often require physically moving one optical clock near another. However, constructing a robust portable system is challenging for this complex experimental apparatus. Here, we report on experiments and design efforts for developing portable Yb optical lattice clocks with systematic uncertainty $<10^{-17}$ employing automatic systems for optical alignment and locking, despite a compact package of ~$1.5$ m$^3$. Additionally, we provide a brief update on recent developments and improvements on laboratory-based Yb optical lattice clocks at NIST.