[IEEE 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Paris, France (2018.7.8-2018.7.13)] 2018 Conference on Precision Electromagnetic Measurements (CPEM 2018) - Optical Frequency Measurements at 1×10?18 Uncertainty with Ytterbium Optical Lattice Clocks

摘要： We describe ytterbium optical lattice clocks under development at NIST. This includes the characterization of optical frequency stability and uncertainty, as well as measurements between two independent clocks, at the 10-18 level. We also report on optical frequency ratio measurements with other optical clocks at NIST.