Downward the temperature scale

Approaches to deep cooling of atomic gases are discussed. The delta kick cooling and adiabatic expansion as well as the limitations of the former are considered. The applicability of hollow optical dipole traps based on radiation of near-resonance transition frequency in atoms is shown. The possibility of designing such traps with a size of ∼1 mm is analysed and the prospects for their use for cooling atoms by evaporation and adiabatic expansion are discussed. (paper)