Theoretical study of the recording density limit of a near-field photochromic memory

The recording density limit of a near-field optical memory that uses a photochromic medium was theoretically studied by use of Shannon’s information theory. Shot noise and material noise were taken into account in the analysis of the signal-to-noise ratio. The conventional recording density limit, which is defined by the inverse of the minimum recorded mark area, and Shannon’s recording density limit were evaluated. The conventional recording density limit was 1011–1012 bits/cm2, and Shannon’s recording density limit was 1012–1013 bits/cm2.