An optical head in which a graded index (GRIN) lens is provided. The optical
head
includes a slider connected to an arm and flying a predetermined distance above
a recording layer for data recording, a GRIN lens mounted in the slider for focusing
an incident beam to form a light spot of a predetermined size on its exit surface
adjacent to the recording layer, and a light-emitting unit for emitting the incident
light to the GRIN lens.