Continuously tunable sub-half-wavelength localization via coherent control of spontaneous emission

We propose a continuously tunable method of sub-half-wavelength localization via the coherent control of the spontaneous emission of a four-level Y-type atomic system,which is coupled to three strong coupling fields including a standing-wave field together with a weak probe field.It is shown that the sub-half-wavelength atomic localization is realized for both resonance and off-resonance cases.Furthermore,by varying the probe detuning in succession,the positions of the two localization peaks are tuned continuously within a wide range of probe field frequencies,which provides convenience for the realization of sub-half-wavelength atomic localization experimentally.