New approaches in deep laser cooling of magnesium atoms for quantum metrology

摘要

Two approaches for solving the long-standing problem of deep laser cooling of neutral magnesium atoms are proposed. The first one uses optical molasses with orthogonal linear polarizations of light waves. The second approach involves a 'nonstandard' magneto-optical trap (NMOT) composed of light waves with elliptical polarizations (in general). Both the widely used semiclassical approach based on the Fokker-Planck equation and quantum treatment fully taking into account the recoil effect are employed for theoretical analysis. The results show the possibility of obtaining temperatures lower than 100 mu K simultaneously with a large number of cold atoms similar to 10(6) divided by 10(7). A new velocity-selective cooling technique allowing one to reach the microkelvin temperature range is also proposed. This technique may have some advantages over, for instance, the shallow-dipole-trap technique utilized by other authors. In the case of magnesium atoms this new technique may be used for obtaining a large number of ultracold atoms (T similar to 1 mu K, N > 10(5)). Such a large number of ultracold atoms is crucial issue for metrological and many other applications of cold atoms.