Abstract

Sideband laser cooling has become a very efficient method to prepare ions in the vibrational ground state V = 0 of an harmonic trap of frequency ω_v [1]. The resolved sideband regime is obtained when the width of the excited state of the two-level system is much smaller than ω_v. This condition is conveniently fulfilled when using Raman transitions between two long lived states. In the Lamb-Dicke regime, the rms size of the fundamental vibrational state Δx is much smaller than λ/2π where λ is the wavelength of the cooling transition. In this regime a two-level ion excited from the n_v. vibrational level in the ground state to n_v - 1 in the excited state, decays mostly into n_v - 1 in the ground state. Using this method. Monroe et al. [1] prepared an ion in the ground state of a three-dimensional trap 92 % of the time.

© 1998 IEEE