An Octupole Magneto-Optical Trap for Gray-Molasses Cooling of Potassium-41

Potassium-41 is challenging to cool and trap optically due to its poorly resolved hyperfine structure. This challenge can be largely overcome with gray-molasses cooling on the D1 line. Here we present our results implementing D1 gray-molasses cooling for potassium-41 in a unique octupole-symmetry magneto-optical trap. The octupole symmetry expands the region of nearly zero magnetic field at the center of the trap, which enhances the effectiveness of sub-Doppler processes. The enhanced cooling is expected to improve loading of an optical dipole trap from the molasses.