| 摘要 |
An apparatus for reading from a multilayer holographic storage medium with a coaxial arrangement of a reference beam and a reconstructed object beam is described. The apparatus has an objective lens for focusing the reference beam into the multilayer holographic storage medium such that the reference beam has a focal point behind or in front of a reflective layer of the multilayer holographic storage medium, wherein a distance between the objective lens and the multilayer holographic storage medium is set in accordance with an addressed layer of the multilayer holographic storage medium, and an imaging system with a fixed lens of focal length f and a movable lens of focal length f for re-collimating a reconstructed object beam, wherein for a specific position of the movable lens the imaging system assumes a 4f configuration. For re-collimating the reconstructed object beam the apparatus is adapted to shift the movable lens of the 4f imaging system by substantially twice the shift of the objective lens necessary for addressing a specific layer of the multilayer holographic storage medium. |
