<title>Ultrahigh-density recording based on third-order optical nonlinearities</title>

Abstract

High density and high data rate are two key points in the development of optical data storage. The aim of this contribution is to report the ultrahigh density recording based on third-order non-linearities (TONL). Studies on the laser beam intensity-dependent refractive-index changes of TONL media, either organic or inorganic, were carried out on the basis of classical electromagnetic field theory. The graphic solutions of the theory and the experimental evidence indicate that materials with large susceptibilities, (chi) (3), and ultrafast response due to dispersive-NL or saturated absorption-NL have good optical switching properties which can be described by an- or multi-optical hysteresis loops and used as the mask layers of super-RENS (Super- resolution near-field structure). On the other hand, the numerical solutions of the wave functions give the third-order nonlinear optical dynamics of direct-gap or indirect-gap semiconductors due to band-filling effect or photon-excited electron-hole generation and recombination processes. Based on TONL, an optimized structure for ultrahigh density recording can be designed. Using miliwatts in power, picosecond in response and having the spot size in the range of n (1 approximately 5) yields 10 n nanometer, these well-designed media are now physically possible in practice.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.