Optical imaging beyond the diffraction limit via dark states
  We study the possibility of creating spatial patterns having subwavelength size by using the so-called dark states formed by the interaction between atoms and optical fields. These optical fields have a specified spatial distribution. Our experiments in Rb vapor display spatial patterns that are smaller than the length determined by the diffraction limit of the optical system used in the experiment. This approach may have applications to interference lithography and might be used in coherent Raman spectroscopy to create patterns with subwavelength spatial resolution. 
Hebin Li, Vladimir A. Sautenkov, Michael M. Kash, Alexei V. Sokolov,   George R. Welch, Yuri V. Rostovtsev, M. Suhail Zubair...