Abstract text

An optical information recording and reproducing apparatus includes an optical pickup, a phase conjugate optical system, a disc cure optical system, and a defect discrimination optical system; and an optical detector that receives a light emitted from the defect discrimination optical system and transmitted through or reflected from an optical information recording medium. A reference light and a signal light emitted from the optical pickup are irradiated onto the optical information recording medium to record and reproduce digital information by using a holography.