| 摘要 |
The present invention relates to an apparatus (1) for reading from and/or writing to transmission type holographic storage media (19), and more specifically to a coaxial type apparatus (1) for reading from and/or writing to transmission type holographic storage media (19) with two or more reference beams (7', 7"), which has an improved Signal to Noise Ratio. The apparatus (1) has a coaxial arrangement of two or more reference beams (7', 7") and an object beam (8) or a reconstructed object beam (21). The reference beams (7', 7") are arranged on a circle around the object beam (8) or the reconstructed object beam (21) in a Fourier plane of the apparatus (1) behind the holographic storage medium (19). A mirror (27) is located in or close to this Fourier plane, which is designed such that it reflects the object beam (8) or the reconstructed object beam (21) without reflecting the reference beams (7', 7"). |
