System and material aspects of volumetric bit-wise optical data storage

Abstract

There are several primary factors that limit the data capacity of a volumetric bit-wise optical data storage system. Firstly, the data density in each layer is limited by the spot size formed at the focus of the objective lens. The spherical aberration induced by the medium also limits the maximum depth that an optical system can reach with diffraction limited focus. A second primary factor is the undesired detection of data from layers other than the layer at the laser focus, which is an effect called inter-layer crosstalk. In the last, the transmission and the reflection rate of the medium sets the limit of the number of the data layers for a given laser diode. In the modeling, the inter-layer crosstalk of volumetric bit-wise storage systems is simulated by using three methods. Several far-field and near-field systems with spherical aberration compensators are presented. In addition, the maximum surface densities of these systems are discussed. A dynamic test stand equipped with a tracking servo is built for testing the fluorescent material performance in a simulated space environment. Coupon samples made of Super-Rens material are tested in another dynamic test stand equipped with a focus servo. Controls of writing conditions for Super-Rens material are investigated with respect to the focus spot speed and data rate. Overall, this dissertation provides a description of volumetric bit-wise optical data storage technology, in terms of the system and material aspects, through simulation and experiments.