Transportable Strontium Optical Lattice Clocks Operated Outside Laboratory at the Level of 10−18 Uncertainty

Abstract

AbstractTransportable strontium optical lattice clocks are developed with a fractional uncertainty of 5.5 × 10−18 for applications outside laboratories. A single clock consists of a spectroscopy chamber and two laser boxes, where all lasers are based on external cavity diode lasers with an adjustment‐free, laser‐welded output coupler. When this system is transported from the laboratory at RIKEN to a broadcasting tower, the instruments experience acceleration change of 4 G at maximum. However, no serious optical misalignments are found. The demonstration opens up field applications of optical atomic clocks resolving a centimeter height difference.