Photoionization loss in simultaneous magneto-optical trapping of Rb and Sr

TL;DR

This paper investigates the simultaneous trapping of Rb and Sr atoms, focusing on how photoionization by Sr's cooling laser causes Rb atom loss, and measures the photoionization cross section to inform future quantum mixture experiments.

Contribution

It provides the first measurement of Rb's photoionization cross section at 461 nm during simultaneous MOT of Rb and Sr, highlighting loss mechanisms relevant for quantum mixture creation.

Findings

Measured Rb photoionization cross section as 1.4(1)×10^{-17} cm^2

Identified photoionization as a significant loss process in dual-species MOTs

Implications for achieving large Rb atom numbers in quantum degenerate mixtures

Abstract

We demonstrate the simultaneous magneto-optical trapping (MOT) of Rb and Sr and examine the characteristic loss of Rb in the MOT due to photoionization by the cooling laser for Sr. The photoionization cross section of Rb in the $5P_{3/2}$ state at 461 nm is determined to be $1.4(1)\times10^{-17}$ cm$^2$. It is important to consider this loss rate to realize a sufficiently large number of trapped Rb atoms to achieve a quantum degenerate mixture of Rb and Sr.