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
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e
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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.