Magneto-optical polarization rotation in a ladder-type atomic system for tunable offset locking

TL;DR

This paper presents a tunable laser frequency locking method using magneto-optical polarization rotation in rubidium vapors, enabling large two-photon detuning adjustments for precise laser stabilization.

Contribution

It introduces a novel, easily tunable two-photon offset locking scheme based on magnetic field-induced polarization rotation in warm rubidium vapors.

Findings

Achieved two-photon detuning up to 700 MHz.

Demonstrated strong tunability of the offset frequency.

Enabled stable laser locking with magnetic field control.

Abstract

We demonstrate an easily tunable locking scheme for stabilizing frequency-sum of two lasers on a two-photon ladder transition based on polarization rotation in warm rubidium vapors induced by magnetic field and circularly polarized drive field. Unprecedented tunability of the two-photon offset frequency is due to strong splitting and shifting of magnetic states in external field. In our experimental setup we achieve two-photon detuning of up to 700 MHz.