Two-Photon Dichroic Atomic Vapor Laser Lock Using Electromagnetically Induced Transparency and Absorption

TL;DR

This paper presents a novel laser locking technique using two-photon EIT and absorption in rubidium vapor, enabling stable laser frequency control up to 1.5 GHz offset from atomic resonance.

Contribution

The authors introduce a two-photon dichroic atomic vapor laser lock leveraging EIT and absorption, demonstrating effective frequency stabilization in a ladder atomic configuration.

Findings

Achieved laser locking up to 1.5 GHz off resonance

Error signal derived from polarization-dependent transparency and absorption

Model accurately predicts experimental signals

Abstract

We demonstrate a technique to lock the frequency of a laser to a transition between two excited states in Rb vapor in the presence of a weak magnetic field. We use a ladder configuration from specific hyperfine sublevels of the 5S 1/2, 5P 3/2, and 5D 5/2 levels. This atomic configuration can show Electromagnetically Induced Transparency and Absorption processes. The error signal comes from the difference in the transparency or absorption felt by the two orthogonal polarizations of the probe beam. A simplified model is in good quantitative agreement with the observed signals for the experimental parameters. We have used this technique to lock the frequency of the laser up to 1.5 GHz off atomic resonance.