Towards 1x10^-18 accuracy in an optical lattice clock.
I will give an overview of the atomic side of things in the Optical Frequency Measurements Group at NIST Boulder. Having demonstrated an two-clock instability at the 10^-18 level, the Yb lattice clocks are now in the process of evaluating systematic effects at the same level. The long dominant black body radiation shift has recently been characterized at the 1x10^-18 level. Additionally, the DC Stark shifts due to stray electric charge and quadratic Zeeman effects are currently being evaluated at or below the 10^-18 level. Two prominent systematic effects remain, namely, the AC stark shifts from the lattice trapping light and first order Doppler shifts arising from either technical or quantum mechanical origins. To study lattice intensity effects across an order of magnitude in trap depth, we have constructed a lattice-build-up-cavity around our ultra-cold atomic sample. These most recent systematic characterizations have been aided by a next generation clock laser, and I will briefly describe our first efforts to characterize it. I will also mention the newest results from the Ca experiment.