Hologram recording/reproducing device and hologram reproducing device

A hologram recording/reproducing device that records information onto a medium by a light beam emitted from a laser light source and passing through a forward path, and that reproduces the information recorded on the medium by the light beam passing through a backward path, the forward path having optical components disposed in an area extending from the laser light source to the medium, the backward path having optical components disposed in an area extending from the medium to an array light detector, the hologram recording/reproducing device comprising:

• a spatial-light modulator disposed in the forward path and adapted to generate signal light and reference light from the light beam emitted from the laser light source, the signal light and the reference light being spatially divided from each other and having a common light path;
• a first objective lens disposed in the forward path and adapted to focus the signal light and the reference light traveling from the spatial-light modulator onto the medium;
• a second objective lens disposed in the backward path and adapted to form a hologram image on the array light detector based on reproduction light traveling from the medium;
• and
• a polarization-dependent diffraction element disposed in the backward path and in a real-image plane of a hologram, the diffraction element being adapted to diffract the reference light incident upon the array light detector from the second objective lens.