Controlling the phase of a light beam with a single molecule
  We employ heterodyne interferometry to investigate the effect of a single organic molecule on the phase of a propagating laser beam. We report on the first phase-contrast images of individual molecules and demonstrate a single-molecule electro-optical phase switch by applying a voltage to the microelectrodes embedded in the sample. Our results may find applications in single-molecule holography, fast optical coherent signal processing, and single-emitter quantum operations. 
M. Pototschnig, Y. Chassagneux, J. Hwang, G. Zumofen, A. Renn and V.   Sandoghdar
quant-ph physics.optics