NANO-CDs WITH 400 GBIT/IN² DATA STORAGE DENSITY. Present compact disks have data storage densities that approach 1 Gbit/in². IBM has tested disks with densities of 45 Gbit/in², using electron lithography for writing 50-nm features, and a scanning-microscope proximal probe for read-back. Now, Peter Krauss and Stephen Chou (chou@ee.princeton.edu) at the University of Minnesota have achieved 10-nm features using nano- imprint lithography for writing and a proximal probe for reading. For such a nano-CD to be useful, however, more robust probe tips will have to be developed, along with multi-tip arrays for faster readout. (Applied Physics Letters, 24 November 1997.)