Abstract

A primary motivation for the original development of optical recording was that the technique allowed a much smaller area for the storage of a bit of information than did the magnetic techniques of that time. Most early data recording was by ablative effects, the formation of "pits" in an optical media. Today, storage may be by ablation, magneto-optic effects, or phase changes. The basic optical principles remain the same for all recording techniques. In general, recording laser light that has a gaussian-like spatial beam profile is expanded to fill the optics to the $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$e^2$}\right.$ intensity points of the beam profile and to focus the light onto the recording medium. The recorded spots are formed with a diameter of approximately equal to the full-width-at-half-power (FWHP) of the primary central lobe of the diffraction pattern on the medium.

© 1992 Optical Society of America