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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Cavity enhanced image recording for holographic data storage

Miller, Bo E., Takashima, Yuzuru 08 September 2016 (has links)
Previously, we proposed and experimentally demonstrated that optical cavities can be employed in recording and readout of plane wave holograms to improve data rates in Holographic Data Storage Systems (HDSS). However, there were some concerns about whether these techniques would be applicable to page based HDSS where signal beams are image bearing and have multiple wave vectors. We have consequently demonstrated cavity enhanced writing of image bearing holograms in Fe: LiNbO3 with a 532 nm wavelength, CW, single mode, DPSS, Nd: YAG, laser with a cavity on the reference arm. The diffraction efficiency was monitored by pseudo-phase-conjugate readout during the recording process. Additionally, standing wave cavity recording was described as inappropriate to HDSS due to introducing additionally gratings to the recording process. The balancing of these grating strengths is analyzed relative to a trade-off in dynamic range consumption vs. data rates and the elimination of the extra gratings via quarter wave plates and isotropic recording media is proposed.
2

Cavity enhanced eigenmode multiplexing for volume holographic data storage

Miller, Bo E., Takashima, Yuzuru 23 August 2017 (has links)
Previously, we proposed and experimentally demonstrated enhanced recording speeds by using a resonant optical cavity to semi-passively increase the reference beam power while recording image bearing holograms. In addition to enhancing the reference beam power the cavity supports the orthogonal reference beam families of its eigenmodes, which can be used as a degree of freedom to multiplex data pages and increase storage densities for volume Holographic Data Storage Systems (HDSS). While keeping the increased recording speed of a cavity enhanced reference arm, image bearing holograms are multiplexed by orthogonal phase code multiplexing via Hermite-Gaussian eigenmodes in a Fe: LiNbO3 medium with a 532 nm laser at two Bragg angles for expedited recording of four multiplexed holograms. We experimentally confirmed write rates are enhanced by an average factor of 1.1, and page crosstalk is about 2.5%. This hybrid multiplexing opens up a pathway to increase storage density while minimizing modifications to current angular multiplexing HDSS.

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