ACHROMATIC LENSES FOR ATOMS USING VELOCITY-DEPENDENT LIGHT-INDUCED POTENTIALS

We propose achromatic lenses for atoms based on the induced dipole for ce in near-resonant spatially varying light fields. The velocity depen dent focal length of ''standard'' dipole force lenses is partly compen sated by making the detuning velocity-dependent through the Doppler ef fect. For instance, for a longitudinal velocity distribution with a re lative width, Delta v/v approximate to 0.2 a variation in focal length of less than 3% can be achieved both for thin and for thick lenses. T his is an order of magnitude smaller than previous lenses based on the dipole force, and hence such lenses could have interesting applicatio ns in atom microscopes and atom lithography.