Laser Cooling in the Recoil Domain

F. Bardou, John Lawall, Bruno Saubaméa +4 more

Nir Davidson, H. J. Lee, Mark A. Kasevich +1 more

I. E. Mazets, Boris G. Matisov

Liang Liu

S. L. Rolston, Paul D. Lett, William D. Phillips

The usual case in laser cooling is that the atomic linewidth ħγ is much greater than the recoil energy ER = ħ2k2/2 m. Considering the recent demonstration of laser cooling to kBT <<ħγ,1 It seems reasonable to reconsider laser cooling where ERħγ. In this case the Doppler shift ħk2/m of a recoil velocity is large compared to the linewidth and an analytic treatment is difficult. We have developed a Monte Carlo simulation of 3-D laser cooling (optical molasses) which applies to any value of ħγ/ER.

Anastasia Kirpichnikova, Прудников Олег Николаевич, R. Ya. Ilenkov +2 more

Based on the numerical solution of the quantum kinetic equation for the atomic density matrix, which makes it possible to accurately take into account the recoil effects in the interaction of atoms with field photons, we have studied the limits of laser cooling of atoms using closed optical transitions characterised by different recoil parameters (the ratio of the recoil energy to the natural linewidth). It is shown that for optical transitions with an insufficiently small recoil parameter, the polarisation effects, which lead to the possibility of sub-Doppler laser cooling, lose their efficiency and do not ensure an attainment of the temperature below the Doppler limit. The analysis performed allows one to outline the boundaries of the sub-Doppler theory of laser cooling of atoms.