Cooling and deflection of atoms in a standing laser wave and a squeezed vacuum

Pasi Ryytty, M. Kaivola, C.G. Aminoff

Davıd L. Andrews, David S. Bradshaw

Pasi Ryytty, M. Kaivola, C.G. Aminoff

Robert Graham, Daniel F. Walls, Weiping Zhang

In this paper, the use of squeezed light in laser cooling is investigated. We find that in a traveling-wave laser field, a two-level atom in a squeezed vacuum cannot be cooled to a lower temperature than in normal vacuum. For a two-level atom in a standing-wave laser field, if it is tuned from the resonant region, the conclusion is the same as in the traveling-wave case. However, near the resonant region, the atom in a standing-wave field can achieve a lower temperature than Doppler limit.

Ghosh, Pradip N

Yaakov Shevy

The process of laser cooling in a quasi resonant standing laser wave is one of the principal technics of laser cooling of atoms. Recent advances in this field include breaking both the "Doppler and the recoil limits". On another front modification of the quantum statistical properties of the "vacuum" fluctuations by squeezing has been achieved in the laboratory. It is, therefore, interesting to find what is the nature of the modification of the laser cooling process when the atoms are also embedded in squeezed vacuum. Such a state can be produced in principle by a degenerate parametric amplifier whose input are vacuum fluctuations. It is shown that due to the modified decay rates of an atom which is embedded in such a state, profound modification of the cooling processes in a standing wave is achieved . Among the important results obtained is the change of sign of the stimulated force from a heating force in normal vacuum to a cooling force in squeezed vacuum. This phenomenon can result in cooling forces more than two orders of magnitude larger than the maximum force in normal vacuum. In this talk the method for calculating the force in squeezed vacuum will be given. The modified force will be compared to the force in normal vacuum and finally the practical implications of these results for laser cooling will be discussed.