# Magic polarization for light shift cancellation in two-photon optical clocks

## TL;DR

This paper introduces a simple method using a magic polarization to cancel probe laser light shifts in two-photon optical atomic clocks, enhancing their accuracy by controlling light-induced frequency shifts.

## Contribution

It identifies a magic polarization angle where light shifts are canceled and demonstrates how polarization controls both light shift suppression and excitation rate.

## Key findings

- Magic polarization cancels differential light shifts.
- Polarization controls excitation rate independently.
- Estimated magic polarization angles for calcium and strontium clocks.

## Abstract

We find a simple solution to the problem of probe laser light shifts in two-photon optical atomic clocks. We show that there exists a magic polarization at which the light shifts of the two atomic states involved in the clock transition are identical. We calculate the differential polarizability as a function of laser polarization for two-photon optical clocks based on neutral calcium and strontium, estimate the magic polarization angle for these clocks, and determine the extent to which probe laser light shifts can be suppressed. We show that the light shift and the two-photon excitation rate can be independently controlled using the probe laser polarization.