Number 49 (Story #1), September 26, 1991 by Phillip F. Schewe and Ben Stein HIGH INDEX OF REFRACTION AND LOW ABSORPTION can be achieved simultaneously in certain materials using quantum interference effects. Marlan O. Scully (505-277-1522) of the University of New Mexico and his colleagues at the Max Planck Institute for Quantum Optics (Munich) first prepare a sample of atoms (e.g., a vapor of sodium atoms) in a "coherent state" with the help of a dye laser, which excites transitions between each of two hyperfine sublevels of the atoms' ground state. This creates a resonant condition which interferes with transitions to a separate, higher-energy state, and hence reduces the absorption of light corresponding to that transition (or, in other words, rendering the sample of atoms transparent at that wavelength). Unlike other induced-transparency experiments, Scully's sample of coherent atoms possesses a high index of refraction. Such low-absorption, index-enhanced optical matter might have applications in laser particle accelerator schemes, in optical microscopy, and in studies of the electroweak force in atoms. (Upcoming article in Physical Review Letters.)