Two-dimensional Sub-wavelength Atom Localization of a Four-Level Λ-type Atomic System with two Adjacent Lower Levels Via Probe Absorption

Two-dimensional atom localization of a four-level Λ-shaped atom with two adjacent lower levels interacting with two orthogonal standing wave fields is considered. By measuring the probe field absorption, spatial information of position of a moving atom is obtained in x−y plane. The position of atom through two-dimensional standing wave field strongly depends on the intensity of standing waves, detuning of the probe and standing wave fields. Choosing the appropriate controlling parameters, the two-dimensional atom localization through the standing wave fields in a sub-wavelength domain will be achieved.