Subrecoil Raman Cooling of Cesium Atoms

Abstract

We use velocity-selective Raman pulses generated by two diode lasers to cool cesium atoms in 1 dimension to an r.m.s. of 1.2 mm/s. This is about 1/3 of the single-photon recoil velocity vrec = ℏk/M, where ℏk is the photon momentum and M the atom's mass. The corresponding effective temperature is a factor of 9 below the single-photon recoil temperature given by kB Trec/2 = 1/2Mvrec2. Because of the high cesium mass, this temperature is only (23 ± 5) nanokelvin, the lowest 1D kinetic temperature reported to date.