Faraday-Ramsey rotation measurement in a thin cell as an analogy to an atomic beam

TL;DR

This paper demonstrates that micron-thin vapor cells can replicate atomic beam behavior for spin coherence measurements, enabling compact and scalable quantum sensors without the need for bulky setups.

Contribution

The study introduces a novel method using thin vapor cells to mimic atomic beam properties, facilitating miniaturized spin coherence measurements.

Findings

Observation of the Faraday-Ramsey effect in a 5 μm rubidium cell

Successful demonstration of Ramsey fringes without buffer gas or coatings

Validation of the model through experimental results

Abstract

Atomic beams are powerful tools for measuring spin coherence in hot vapors but require bulky setups, limiting device miniaturization. We demonstrate that micron-thin vapor cells can mimic atomic beam behavior by exploiting geometry-dependent velocity filtering. In a 5 {\mu}m rubidium cell, coherence is preserved for atoms moving parallel to the cell walls, enabling observation of the Faraday-Ramsey effect without buffer gas or anti-relaxation coatings. Using a spatially displaced pump-probe scheme and magnetic field scanning, we achieve clear Ramsey fringes and validate our model experimentally. This technique offers a compact alternative to atomic beam systems, supporting scalable sensors and frequency standards.