Description
After laboratory optical atomic clocks have reached fractional frequency uncertainties in the 10$^{-18}$ regime, it is an ongoing task to miniaturize these complex clocks and make them transportable and in-field deployable, without compromising their performance. This effort is primarily motivated by promising prospects in geodesy. Together with accurate frequency transfer via fiber links, these clocks can measure gravitational potential differences in the 0.1 m$^2$/s$^2$ regime (corresponding to 'cm' height differences on Earth’s surface) with high spatial and temporal resolution. Thus, they could be used to establish an accurate height reference system. At PTB, we have been operating a transportable optical clock based on neutral strontium atoms in a 1-D optical lattice. This clock previously had been to international measurement campaigns in Modane, Turin, Paris, and Munich.
Here we present the progress in the development of our new transportable clock, to achieve a lower uncertainty and better instability. These upgrades come in the form of a new physics package employing a single-beam pyramid MOT for the first and second stages of cooling, better stray magnetic field shielding, a lower background pressure in the science chamber and a temperature shield for better thermal uniformity during the clock interrogation phase. These changes along with the use of a new transportable cavity (instability: 1.6 × 10$^{-16}$) operating at the subharmonic of the clock transition are expected to push the fractional frequency uncertainty to the low 10$^{-18}$ regime.
This work receives funding from the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany's Excellence Strategy - EXC-2123 QuantumFrontiers - 390837967 and SFB 1464 TerraQ - 434617780. It is supported by the Max Planck-RIKEN-PTB Center for Time, Constants and Fundamental Symmetries.
| Presenter name | Chetan Vishwakarma |
|---|---|
| How will you attend ICAP-27? | I am planning on in-person attendance |
