Stimulated Slowing of Yb Atoms on the Narrow $^1S_0\rightarrow^3P_1$ Transition

TL;DR

This paper models and demonstrates stimulated laser forces on Yb atoms using narrow transition light, predicting enhanced MOT loading rates and velocity ranges through modulation techniques.

Contribution

It introduces a detailed numerical model for stimulated forces on Yb atoms and shows how modulation improves cooling efficiency and atom loading rates.

Findings

Stimulated forces can increase Yb atom slowing by up to 60 times the radiative force.

Square wave modulation nearly doubles the velocity range of the stimulated force.

MOT loading rate can be improved by up to 70% using these techniques.

Abstract

We analyzed bichromatic and polychromatic stimulated forces for laser cooling and trapping of Yb atoms using only the narrow $^1S_0\rightarrow^3P_1$ transition. Our model is based on numerical solutions of optical Bloch equations for two-level atoms driven by multiple time-dependent fields combined with Monte-Carlo simulations, which account for realistic experimental conditions such as atomic beam divergence, geometry, and Gaussian laser modes. Using 1 W of laser power, we predict a loading rate of $\approx 10^8$ atoms/s into a 556 nm MOT with a slowing force of $\approx 60F_{rad}$. We show that a square wave modulation can produce similar stimulated forces with almost twice the velocity range and improve the MOT loading rate of Yb atoms by up to 70%.