A NEW READOUT TECHNIQUE FOR CD-ROM MULTILEVEL OPTICAL DATA STORAGE
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PublisherThe University of Arizona.
RightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
AbstractA technique is presented that utilizes an on-axis intensity measurement to detect the reflected light from a multiple CD-ROM surface. The thesis includes a computer simulation of the detected signal for scans of various structures and discusses finite size detector effects. A suitably sized detector passes 77% of the total light flux at the detector plane without affecting the depth discrimination property of the technique. Experimentally, a breadboard Height Readout System (HRS) could detect height differences on test relief structures. A signal to noise ratio was obtained that corresponds to a noise equivalent height sensitivity of 30 Angstroms. Therefore, the HRS could discriminate between five levels on the test structure. An addition to the new technique uses a phase plate to determine if the focused beam is going into or out of a pit. Thus, the storage capability per unit area on the disk surface can be increased.
Degree ProgramGraduate College