Magic wavelengths for lattice trapped Rubidium four-level active optical clock

TL;DR

This paper calculates magic wavelengths for lattice trapping of Rubidium in a four-level active optical clock, minimizing AC Stark shift to achieve ultra-high frequency stability.

Contribution

It identifies specific magic wavelengths and optimal laser parameters to reduce frequency shifts in Rubidium optical clocks.

Findings

Several magic wavelengths suitable for trapping are identified.

The fractional frequency uncertainty can be reduced below 10^-18.

AC Stark shift is the dominant factor affecting clock stability.

Abstract

After pumped from $5s_{1/2}$ ground state to $6p_{1/2}$ state, the population inversion between $6s_{1/2}$ and $5p_{1/2,3/2}$ will be established for Rubidium four-level active optical clock. In this paper, we calculate AC Stark shift due to lattice trapping laser which dominates the frequency shift of clock transition in lattice trapped Rubidium four-level active optical clock. Several magic wavelengths are found that can form desired optical lattice trapping potential. By choosing a proper intensity and linewidth of trapping laser, the fractional frequency uncertainty of clock transition due to AC Stark shift of trapping laser, is estimated to be below 10^-18