Optical forces on atoms in nonmonochromatic light

We have recently begun to explore the very strong optical forces that can be exerted on atoms by polychromatic light. Unlike the radiative force that is limited to be less than ℏkγ/2 in monochromatic light or the dipole force that alternates on a wavelength scale in a monochromatic standing wave, limiting its utility, these new forces have very attractive features. Not only is their strength far greater than Frad, but also their velocity range is far greater than γ/k, so that beam slowing can be accomplished without Doppler compensation in distances measured in millimeters instead of meters. These forces have been implemented by modulation of a single-frequency laser or by combination of the light of two different single-frequency lasers.