Laser cooling of lithium atoms by a strong standing wave

Dipole force has been used to deflect an atomic beam by large angles and to effect a large increase of the atomic beam intensity. The cooling of transverse velocities of lithium atoms in an atomic beam in the regime of very high standing wave intensity (Rabi frequency ≈ 50) and long interaction time (approximately 5 μs) by using a standing wave with an asymmetric beam waist has been investigated. The transverse position of the atoms is detected by an iridium hot wire located approximately 30 cm downstream from the standing wave. The force for various detunings from resonance has been studied. The hot wire signal when the laser frequency is tuned several linewidths to the blue shows that atoms with very small transverse velocity are cooled, whereas those with greater velocity are heated. Data for two different values of red detuning show that atoms with very small velocities (depending on the magnitude of the detuning) are heated and all other velocities are cooled.