A laser beam recording system for exposing a photoresist master disc
having a photoresist layer formed over a substrate for making a hybrid
optical recording disc having a read only (ROM) portion and a writable
portion, including a first optical modulator for modulating an intensity
of a first laser beam having a wavelength selected to provide activating
radiation to expose a pattern in the photoresist layer formed over the
substrate of the master disc between a lower intensity for exposing a
groove in the photoresist layer and a higher intensity for exposing the
groove and a pattern of depressions in the groove in the photoresist
layer; and a second optical modulator for frequency-modulating an
intensity-modulated second laser beam with a wobble-frequency to cause
the exposed groove to be a continuously frequency-modulated groove. The
recording system also includes a laser beam modulation control system for
controlling the operation of the first and second optical modulators to
form a continuously frequency-modulated exposed groove with exposed
depressions in the ROM portion of the exposed groove. The first and the
second laser beams can be provided by one laser as a single laser beam,
by one laser as two split laser beams, and by a first and a second laser.