Frank PRZYGODDA^*, Joachim KNITTEL, Oliver MALKI, Heiko TRAUTNER, and Hartmut RICHTER

Deutsche Thomson OHG, Hermann-Schwer-Str. 3, D-78048 Villingen-Schweningen, Germany

(Received January 14, 2009; Accepted August 26, 2009)

Random phase masks in object and reference beam of page-based holographic storage systems suppress the DC-peak and improve the overlap of both beams inside the storage material. Furthermore, they allow for a narrow shift-selectivity. In a holographic setup the phase mask has to be introduced at a conjugate image plane of the spatial light modulator (SLM), if it is not fixed directly on the SLM itself. A binary phase mask with cells generating 0 and π phase shifts has to be aligned very accurately with respect to the SLM pixels, otherwise image artifacts disturb the received data page. We present a phase mask, where the phase cells have the size of a data block which consists of a rectangular set of SLM pixels. Additionally, the corresponding data page has no data at the position of phase jumps and thus relaxes the alignment tolerance significantly.

Key words: optical data storage, holography, random phase mask, binary phase mask, tolerance, data format, modulation

^*E-mail address: frank.przygodda@thomson.net