High-Flux Cold Ytterbium Atomic Beam Source Using Two-Dimensional Laser Cooling with Intercombination Transition

TL;DR

This paper presents a method to produce a high-flux, low-temperature ytterbium atomic beam using two-dimensional laser cooling on an intercombination transition, achieving significant flux and low transverse temperature for advanced atomic physics applications.

Contribution

The study demonstrates a novel application of 2D laser cooling on the intercombination transition to produce a high-flux, low-temperature ytterbium atomic beam with potential for further momentum narrowing.

Findings

Achieved transverse temperature of 11 ± 9 μK.

Produced atomic flux of (7.5 ± 1.0) × 10^8 atoms/s.

Maintained low transverse temperature below 23 μK across a velocity range.

Abstract

We demonstrate a high-flux and low transverse temperature atomic beam of ytterbium by applying two-dimensional cooling using the ${}^1\mathrm{S}_0\text{-}{}^3\mathrm{P}_1$ intercombination transition to the cold atomic beam produced by the dipolar-allowed ${}^1\mathrm{S}_0\text{-}{}^1\mathrm{P}_1$ transition. The optimized transverse temperature of $11 \pm 9\,\mathrm{\mu K}$ and an atomic flux of $(7.5 \pm 1.0) \times 10^8\,\mathrm{atoms/s}$ are obtained for the atomic beam whose longitudinal velocity is $30\,\mathrm{m/s}$. The transverse temperature is maintained below $23\,\mathrm{\mu K}$, while the flux is above $6.5 \times 10^8\,\mathrm{atoms/s}$ in the longitudinal velocity range of $22 - 30\,\mathrm{m/s}$. We also discuss the feasibility of further narrowing the transverse momentum width to less than the recoil momentum using the momentum-selective optical transition between the ground state and the long-lived metastable state. The transverse momentum width of our atomic beam, which is narrower than 5.7 times the recoil momentum, is a good starting point for the proposed method.