Thulium Optical Lattice Clock With Zeeman-Insensitive Synthetic Clock Frequency

In this work we discuss interrogation scheme required for the use of synthetic frequency in thulium optical lattice clock and underlying specifics of servo signal generation. In order to achieve insensitivity of the synthetic frequency to periodic oscillations of the magnetic field, simultaneous interrogation of two clock transitions is beneficial, which complicates optimization of digital lock parameters and may result in crosstalk. We used numerical simulations to test the performance of digital locks and verify absence of systematic frequency shifts related to the interrogation scheme.