Ultrafast dynamic holography in nanocrystal solids

We report efficient dynamic gratings in close-packed solids of CdSe nanocry stals. These gratings are formed on the subpicosecond time scale and have d iffraction efficiencies up to 0.5% for film thicknesses of similar to0.5 mu m. Nanocrystal solids combine the best features of inorganic semiconductors (large resonant nonlinearities and high photostability) and organic semico nducting polymers (chemical flexibility and tunability of optical propertie s by simple synthetic means). Additionally, nanocrystal solids allow precis e control over the spectral position of the nonlinear optical response by s imply varying the size of the nanocrystals used in fabricating the solid (q uantum confinement effect). (C) 2001 American Institute of Physics.