Optical Memories and Processing in Time- and Frequency Domain

Baozhu Luo

Research output: ThesisDoctoral Thesis (compilation)

Abstract

Spectral hole burning and photon echoes are the techniques for frequency-selective optical memories, which have the potential to increase areal data storage density by a factor 10**7. They also have the capability to perform in-memory data processing. In this thesis, several materials and techniques for optical memories in the frequency- and time domain have been investigated.

In the frequency domain, ways to increase the storage density and the working temperature were studied using photon-gated spectral hole burning materials of the metal-tetrabenzoporphyrin derivatives. A selection rule for the electron acceptors in the donor-acceptor electron transfer systems was deduced. By doping the material with two different donors a maximum inhomogeneous line width of more than 30 THz was achieved. A polarization holographic technique was established for the formation and detection of spectral holes. Our results indicate that this technique can provide a better signal-to-noise ratio than that achieved by a conventional holographic technique, in particular for samples of poor optical quality.

In the time domain, magnetic field-induced and the intensity-induced dephasing processes were studied in Pr3+ doped in a YAlO3 crystal and a Y2SiO5 crystal, respectively. As a step along the route to make photon echo based optical processing possible, the amplification of photon echo signals by the use of a fiber amplifier (Pr3+-doped ZBLAN) was demonstrated. A gain of 45 was achieved. The erasure of stored data using photon echoes has also been investigated. A technique to diagnose the phase and frequency stability of a light source by the photon echo erasure process was proposed and illustrated. An approach to bit-selective data erasure, that is free from laser phase and frequency fluctuations, is also suggested. A concept for an arbitrary shape pulse generator based on photon echoes and hole-burning was experimentally and theoretically studied.

Finally, a comparison between the properties and capabilities of spectral hole burning and photon echoes was made.
Original languageEnglish
QualificationDoctor
Awarding Institution
  • Atomic Physics
Supervisors/Advisors
  • Kröll, Stefan, Supervisor
Award date1998 Jun 10
Publisher
ISBN (Print)91-628-3024-4
Publication statusPublished - 1998

Bibliographical note

Defence details

Date: 1998-06-10
Time: 10:15
Place: Lecture Hall A, Department of Physics, Sölvegatan 14, Lund, Sweden

External reviewer(s)

Name: Kachru, Ravinder
Title: Dr
Affiliation: SRI International, Menlo Park, California, USA

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Subject classification (UKÄ)

  • Atom and Molecular Physics and Optics

Keywords

  • Optical storage
  • photon echo
  • spectral hole burning
  • nonlinear optics
  • fiber amplifier
  • logical operation
  • phase retrieval
  • polarization holographic recording and retrieval
  • optical processing
  • Atomic and molecular physics
  • Atom- och molekylärfysik
  • Fysicumarkivet A:1998:Luo

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