HOLOGRAPHIC STORAGE SYSTEM USING HOMODYNE DETECTION

摘要

The present invention relates to an apparatus (1) for reading from holographic storage media (13) using a homodyne detection scheme. According to the invention, the apparatus (1) has a light source (2') for generating a reference beam (5) and a local oscillator beam (20), an objective lens (12) for focusing the reference beam (5) into the holographic storage medium in order to generate a reconstructed object beam (14), and an optical path length controller (33, 35) for varying the path length of the local oscillator beam (25) or the reference beam (5). The optical path length controller (33, 35) is adapted to vary the path length of the local oscillator beam (25) or the reference beam (5) by a quarter of the wavelength of the local oscillator beam (25) in order to obtain two quadrature images.