Diffraction Property of Collinear Holographic Storage System

1.1 The collinear volume holographic storage system The collinear storage system was proposed by Optware [1,2]. It is a coaxially aligned optical structure for signal and reference beams, which are encoded simultaneously by the same spatial light modulator (SLM) and the two beams interfere with each other in the recording medium through a single objective lens. The system has been proven a capability of large storage capacity, high transfer rate, short access time, and besides, it is compatible with existing disc storage systems such as CDs and DVDs [3-4]. Recent report of the collinear Volume holographic storage (VHS) has performed a storage density as high as 270 Gbits/inch2 [5]. Many advantages are proposed, including uniform shift selectivity in both radial and tangential directions, a fairly large wavelength shift and a fairly large tilt tolerance [6].