High resolution atomic coherent control via spectral phase manipulation   of an optical frequency comb
  We demonstrate high resolution coherent control of cold atomic Rubidium utilizing spectral phase manipulation of a femtosecond optical frequency comb. Transient coherent accumulation is directly manifested by the enhancement of signal amplitude and spectral resolution via the pulse number. The combination of frequency comb technology and spectral phase manipulation enables coherent control techniques to enter a new regime with natural linewidth resolutions. 
Matthew C. Stowe, Flavio C. Cruz, and Jun Ye