Font Size: a A A

Optical designs for page-based and bit-based holographic data storage systems

Posted on:2008-10-29Degree:Ph.DType:Dissertation
University:Stanford UniversityCandidate:Takashima, YuzuruFull Text:PDF
GTID:1448390005979458Subject:Physics
Abstract/Summary:
In this dissertation, we investigate practical performances and limitations of page-based and bit-based holographic volume recording approaches by comparing the two schemes while taking into account optical aberrations in conjunction with lens designs.; We have shown that the Strehl intensity ratio of the reconstruction reference beam approximates the diffraction efficiency for the bit-based recording. By the Strehl intensity ratio representation, we have compared the media tilt tolerance and shown that an optimum value of the focusing NA (∼0.7) exists to maximize the tilt tolerance for the bit-based approach. Most importantly, the tilt tolerance for the bit-based system is about magnitude larger compared to that of the page-based system.; Lens designs for page-based system involve series steps including first-order power arrangements, third-order designs, fifth-order aberration balancing and ray-trace optimizations. So far, no systematic lens design approach aiming to maximize imaging NA while using less lens elements has been employed.; By focusing on chief-ray deflection angles, the optimum first-order power arrangement, such that a negative element is placed on the Fourier plane, has been identified. Following the first-order design, we have identified that a bi-aspherical meniscus lens or air-spaced spherical lenses are minimum configurations to compensate for all the third-order aberrations.; Balancing of aberrations is essential to increase the imaging NA, but has not been theoretically investigated. By numerically solving expression of variance of wave aberrations, we have shown that four realizable balancing exist and two of them are practically usable and identical. Finally, we have presented high imaging NA designs having single-element (NA ∼ 0.5), double-element (NA ∼ 0.7) and triple-element (NA ∼ 0.8). Also, the imaging and focusing NA of 0.45 system is designed which are usable both for the page- and bit-based holographic recordings.; In conclusion, we have confirmed a high potential of the bit-based holographic storage systems especially in terms of the robustness of the system. We have conducted systematic lens designs of high imaging NA systems having small number of lens elements, which can be a general design guideline for designing lenses in page-based holographic storage systems.
Keywords/Search Tags:Page-based, Holographic, System, Storage, Designs, Imaging NA, Lens, NA &sim
Related items