Mollow triplet

Another experimental proof of the localization of cold atoms at the minima of a periodic optical potential was obtained by recording the resonance fluorescence spectra of cesium atoms trapped in three-dimensional optical molasses (Westbrook et al. 1990) and rubidium atoms in a one-dimensional optical potential (Jessen et al. 1992) The resonance fluorescence spectrum of a motionless two-level atom consists of the well-known Mollow triplet, which includes a central peak at the laser frequency u> and two side components displaced to the red and blue sides by an amount equal to the Rabi frequency (Mollow 1969). For a two-level atom oscillating in a potential well at a frequency lower than the Rabi frequency, each component of the Mollow triplet is split into side components corresponding to changes in the vibrational state of the atom. If the ratio between the oscillation amplitude of the atom in the potential well and the radiation wavelength (the Lamb-Dicke factor) is small, each component of the... 

Mollow triplet contains only the first side components (Fig. 6.6). The ratio between the intensities of the side peaks was used to determine the vibrational temperature of the atoms and to estimate that the localization region of the atoms was of size Azfn X/15. 

Fig. 6.6 (a) Resonance fluorescence of atoms trapped in periodic potential wells. The spectrum is shown near the central component of the Mollow triplet, (b) The quantum transitions of an atom between the vibrational states responsible for the side components. (Reprinted from Jessen et al. 1992 with courtesy and permission of the American Physical Society.)... 

---