# A simple, narrow, and robust atomic frequency reference at 993 nm exploiting the rubidium (Rb) $5\mathit{S}_{1/2}$ to $6\mathit{S}_{1/2}$ transition using one-color two-photon excitation

## TL;DR

This paper demonstrates a simple, stable atomic frequency reference at 993 nm using a one-color two-photon transition in rubidium vapor, suitable for precision measurements and quantum applications.

## Contribution

It introduces a straightforward experimental setup for a robust rubidium-based frequency reference at 993 nm utilizing two-photon excitation.

## Key findings

- Successful demonstration of two-photon transition in rubidium vapor at 993 nm
- The setup is simple and insensitive to magnetic field variations
- Potential for use in precision measurement and quantum technologies

## Abstract

We experimentally demonstrate a one-color two-photon transition from the $5\mathit{S}_{1/2}$ ground state to the $6\mathit{S}_{1/2}$ excited state in rubidium (Rb) vapor using a continuous wave laser at 993 nm. The Rb vapor contains both isotopes ($^{85}$Rb and $^{87}$Rb) in their natural abundances. The electric dipole allowed transitions are characterized by varying the power and polarization of the excitation laser. Since the optical setup is relatively simple, and the energies of the allowed levels are impervious to stray magnetic fields, this is an attractive choice for a frequency reference at 993 nm, with possible applications in precision measurements and quantum information processing.