Measurement of collision frequency shift in strontium optical lattice clock

Cold-collision-shift cancellation and inelastic scattering in a Yb optical lattice clock

Recently, p-wave cold collisions were shown to dominate the density-dependent shift of the clock transition frequency in a 171Yb optical lattice clock. Here we demonstrate that by operating such a system at the proper excitation fraction, the cold-collision shift is canceled below the 5 × 10−18 fractional frequency level. We report inelastic two-body loss rates for P0 -P0 and S0 -P0 scattering....

Measurement and cancellation of the cold collision frequency shift in an 87Rb fountain clock

We measure a cold collision frequency shift in an 87Rb fountain clock that is fractionally 30 times smaller than that for Cs. The shift is -0.38(8) mHz for a density of 1.0(6)x10(9) cm(-3). We study the cavity pulling of the atomic transition and use it to cancel the cold collision shift. We also measure the partial frequency shifts of each clock state finding 2(lambda(10)-lambda(20))/(lambda(1...

Optical Cavity for the Strontium Lattice Atomic Clock

The Sr lattice atomic clock in Jun Ye’s group has been experiencing frequency shifts due to the interaction between the Sr atoms in the optical trap. One possible solution is to change the optical trap in the system such that the Sr atom density, and therefore the interaction between the atoms, is reduced. For this project a test system is necessary to test the vacuum chamber viewports, which i...

The Strontium Optical Lattice Clock: Optical Spectroscopy with Sub-Hertz Accuracy

A transportable optical lattice clock

We present the experimental setup and first results of PTB’s transportable Sr clock. It consists of a physics package, several compact laser breadboards, and a transportable high finesse cavity for the clock laser. A comparison of the transportable system with our stationary optical lattice clock yields an instability of 2.2 × 10−15 √ s/τ for the transportable clock. The current fractional unce...