An apparatus for reading and writing holograms from and to a holographic storage medium uses an object beam and a reference beam both having a first coherence length and being guided along separate optical branches of an optical setup to be imaged to the holographic storage medium. The apparatus includes one or more elements for reducing the coherence length of the reference beam to a second coherence length for reading out a hologram from the holographic storage medium, wherein the second coherence length is shorter than the first coherence length.