Holographic data storage with a planar-integrated optical write-read head

The construction of a write-once-read-many-type optical write-read-head for volume holographic data storage in disk-based photopolymer storage media is discussed. Its design is based on the photonic integration concept called planar-integrated free-space optics. A proof-of-principle demonstrator was fabricated, it contains a 3mm thick fused silica wafer that carries most passive components for the reference and the signal beam relay in the form of diffractive optical elements, a translucent liquid crystal microdisplay, and the CCD sensor of a webcam. Phenanthrenequinone-doped polymethylmethacrylate was chosen as storage material, a DPSS laser with λ = 532nm serves as light source. We report about preliminary experiments to determine suitable exposure parameters for holographic write-read operations, and on the use of data matrix codes for the encoding and decoding of information.