Frequency Domain Optical Storage: The Importance of Photon-Gated Materials

Persistent spectral hole-burning (PHB, also called photochemical hole-burning) permits use of the optical frequency for encoding digital information through the presence and absence of spectral holes that are burned in inhomogeneously broadened absorption lines at low (liquid helium) temperatures. The optical frequency or wavelength at which a given hole is burned acts as an additional dimension for data storage, hence this optical recording scheme has been called Frequency Domain Optical Storage (FDOS). The combination of spectral and spatial data-recording can make storage densities in excess of 1010 bits/cm2 possible; furthermore, since rotation of the recording medium is not necessary, shorter random access times will result. The future success of the FDOS concept will rely on progress in several technological and engineering areas as well as on advances in several critical materials areas1.