Magnetic trapping of an ultracold ³⁹K-⁴⁰K mixture with a versatile potassium laser system

We present a dual isotope magneto-optical trap (MOT), simultaneous sub-Doppler laser cooling, and magnetic trapping of a spin-polarized ³⁹K-⁴⁰K Bose-Fermi mixture realized in a single-chamber setup with an unenriched potassium dispenser as the source of atoms. We are able to magnetically confine more than 2.2 × 10⁵ fermions (F = 9/2 , m  = 9/2) and 1.4 × 10⁷ bosons (F = 2 , m  = 2) with a lifetime exceeding 1.2 s. For this work, we have developed a versatile laser tailored for sub-Doppler cooling of all naturally occurring potassium isotopes and their mixtures. This laser system incorporates innovative features, such as the capability to select an isotope by activating or deactivating specific acousto-optic modulators that control the light seeding tapered amplifiers. Switching between isotopes takes ∼1 µs without any mechanical adjustment of the components.