We report on the achievement of quantum degeneracy in both components of a Bose-Fermi mixture of metastable helium atoms, ${}^4\mathrm{He}^{*}$ and ${}^3\mathrm{He}^{*}$. Degeneracy is achieved via Doppler cooling and forced evaporation for ${}^4\mathrm{He}^{*}$, and sympathetically cooling ${}^3\mathrm{He}^{*}$ with ${}^4\mathrm{He}^{*}$. We discuss our modified implementation, along with the high versatility of our system. This technique is able to produce a degenerate Fermi gas with a minimum reduced temperature of $T/T_F=0.14\left(1\right)$, consisting of $2.5\times {10}^4$ ${}^3\mathrm{He}^{*}$ atoms. Due to the high internal energy of both isotopes single atom detection is possible, opening the possibility of a large number of experiments into Bose-Fermi mixtures.

• Received 17 November 2022
• Accepted 21 February 2023

DOI:https://doi.org/10.1103/PhysRevA.107.033313