Abstract

In laser cooling situations, the random photon recoil of an atom at spontaneous emission increases the temperature. In order to cool below the recoil limit, spontaneous emissions must be avoided. This can be achieved when stationary states within the ground level exist. These dark states form the key ingredients for velocity-selective population trapping (vscpt) [1]. This method allows cooling below recoil temperatures and spatial coherences larger than an optical wavelength. Another advantage of trapping atoms in dark states is that the long-range dipoledipole interaction vanishes. This is important when quantum statistical effects are studied.

© 1998 IEEE