HOLOGRAM RECORDING/REPRODUCING SYSTEM

摘要

A hologram recording/reproducing system records or reproduces information on a recording medium containing an optical interference pattern of a reference light and a signal light as a diffraction grating. The system includes: a light source for generating a coherent light flux; a light generation unit having a signal light region and a reference light region which are inversely symmetric around an optical axis and spatially separating the coherent light flux to a signal light and a reference light propagating in the signal light region and the reference light region; a light interference unit arranged on the optical axis, having a signal light region and a reference light region which are inversely symmetric around the optical axis and coincide with the signal light region and the reference light region for passing the reference light and the signal light, and collecting the reference light and the signal light at different focal points on the optical axis so as to interfere with each other; a recording medium having a hologram recording layer arranged between at least different focal points; and image detection means arranged on the optical axis for receiving light returning from a hologram recording layer via an objective lens optical system when the reference light is applied to the hologram recording layer.