OPTICAL PICKUP DEVICE AND HOLOGRAM RECORDING/REPRODUCING SYSTEM

摘要

An optical pickup device includes: a light source emitting a coherent light; a spatial light modulator formed by a central region arranged on an optical axis of the coherent light and an annular region arranged to surround the central region, for spatially isolating a component of the coherent light which has passed through the central region from a component of the coherent light which has passed through the annular region so as to generate a reference light and a signal light which propagate coaxially in the same direction; an objective lens optical system arranged on the optical axis for applying the signal light and the reference light coaxially toward a hologram recording layer and converging the reference light and the signal light at different focal points; image detection means arranged on the optical axis for receiving the light returning via the objective lens optical system from the hologram recording layer when the reference light is applied to the hologram recording layer; and a polarization plane rotation device formed by a central polarization region arranged on the optical axis and an annular polarization region arranged to surround the central polarization region and differentiating the rotation angles of the polarization planes of the components which have passed through the central polarization region and the annular polarization region.