High Phase-Space Density of Laser-Cooled Molecules in an Optical Lattice

We report laser cooling and trapping of yttrium monoxide molecules in an optical lattice. We show that gray molasses cooling remains exceptionally efficient for yttrium monoxide molecules inside the lattice with a molecule temperature as low as 6.1(6) mu K. This approach has produced a trapped sample of 1200 molecules, with a peak spatial density of similar to 1.2 x 10(10) cm(-3), and a peak phase-space density of similar to 3.1 x 10(-6). By ramping down the lattice depth, we cool the molecules further to 1.0(2) mu K, 20 times colder than previously reported for laser-cooled molecules in a trap.

Automated summary

Laser cooling and trapping of yttrium monoxide molecules in an optical lattice have been achieved, with gray molasses cooling proving to be efficient for achieving a low molecule temperature of 6.1(6) mu K. A trapped sample of 1200 molecules with a high spatial and phase-space density has been produced, with further cooling to 1.0(2) mu K reported, making it 20 times colder than previously achieved for laser-cooled molecules in a trap.