Abstract
We evaluate the resonance-fluorescence spectrum of a bunch of two-level atoms driven by a gradient coherent laser field. The result shows that we can determine the positions of atoms from the spectrum even when the atoms locate within the subwavelength range and the dipole-dipole interaction is significant. This far-field resonance-fluorescence-localization microscopy method does not require point-by-point scanning, and it may be more time efficient. We also give a possible scheme to extract the position information in an extended region without requiring more peak power of the laser. Finally, we also briefly discuss how to perform two-dimensional imaging based on our scheme.