OPTICAL INFORMATION RECORDING/REPRODUCING APPARATUS, AND OPTICAL INFORMATION RECORDING/REPRODUCING METHOD

摘要

PROBLEM TO BE SOLVED: To reduce wavelength fluctuations during reproduction when security of high coherency is prioritized, in a recording/reproducing apparatus utilizing a holography.SOLUTION: An optical information recording/reproducing apparatus for recording an interference pattern between signal light to which information is superposed and reference light in an optical information recording medium as a hologram and reproducing the information by using the reference light from the hologram recorded in the optical information recording medium, includes a light source part for emitting light and a coherency control part for controlling coherency of the light source part. The coherency control part controls the coherency so as to switch coherency to be required for recording and coherency to be required for reproduction to each other.