Entangled photons enhance fluorescence imaging

  Two-photon excitation microscopy is used to image living tissue.  The fluorescence technique uses infrared light and allows deeper penetration of tissue than traditional fluorescence imaging.  But the two-photon process is inefficient for organic materials.  One solution is to increase the intensity of light directed at a sample, but this may damage the sample.  Another solution is to use entangled photons, reports a group led by T. G. Goodson of the University of Michigan.  They report that the technique could enhance two-photon imaging by 10 orders of magnitude.