Number 238 (Story #2), September 1, 1995 by Phillip F. Schewe and Ben Stein AN AREAL DATA STORAGE DENSITY OF 8 GBIT/SQ.IN. has been demonstrated at the University of Oregon (Thomas Mossberg, 503-346-4779). By the encoding of a signal not directly in the form of bits but in the form of an ensemble of laser lightwaves at slightly different frequencies (essentially the Fourier transform of the signal), data can be stored as patterns of excited atoms in a frequency-sensitive medium. The Oregon physicists were able to write the equivalent of 2000 bits of data onto a single spot with an area of about 200 sq. microns. The resulting data storage density is bigger by a factor of 10 than that achieved for standard optical or magnetic recording methods. Another important figure of merit is the density-bandwidth (how much data and how fast): the Oregon figure is 1.5 x 10**17 bits/sq.in./sec., a factor of 3 to 10 larger than previously published reports for non-parallel systems. The material used in the Oregon work---thulium atoms lodged in a crystal---was chosen for its compatibility with the common diode laser (the same used in compact disk players) used to write the data. The researchers feel that even higher data storage densities are possible and that the use of other materials---retaining data for longer periods and at more forgiving temperatures (their current work is at 4-6 K)---will eventually make this new form of data storage highly efficient, fast, and practical. (H. Lin et al., Optics Letters, 1 August 1995.)