Optical molasses

Optical molasses is a laser cooling technique that can cool neutral atoms to as low as a few microkelvin, depending on the atomic species. An optical molasses consists of 3 pairs of counter-propagating circularly polarized laser beams intersecting in the region where the atoms are present. The main difference between optical molasses and an MOT is the absence of magnetic field in the former. Therefore, unlike a MOT, an optical molasses provides only cooling and no trapping.