A patterned-media magnetic recording disk drive uses an optical
system for clocking the write data and a patterned-media disk that has discrete magnetizable data islands with nonmagnetic spaces between the islands, wherein the nonmagnetic spaces contain
optical contrast material. The
optical contrast material may be optically absorptive material, fluorescent material, or a
metal layer that generates surface plasmons when excited by
radiation of a specific
wavelength.
Radiation from a primary
radiation source is directed to a near-field
transducer maintained near the disk surface and a
radiation detector detects radiation reflected back from the
transducer. If the disk has fluorescent material or a
metal layer in the nonmagnetic spaces, then a
secondary radiation source irradiates the fluorescent material or
metal layer with radiation of a specific
wavelength to cause the fluorescent material to emit radiation or the metal layer to generate surface plasmons. As the disk rotates, reflected
optical power from the
transducer varies depending on whether an island or space is under the transducer. The output
signal from the radiation
detector output controls the write
clock.