Holographic memory with fringe stabilizing compensation for recording medium motion
US4104489A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 1977 |
| Grant date | Aug 1, 1978 |
| Priority date | — |
| Expiry date | Feb 15, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0065
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The holographic recording system comprises a pair of aligned first and second Fourier transforming lenses, a holographic beam splitter having a series of random phase illumination holograms at a front focal plane of the first lens and arranged to move in a given direction to successively receive a light beam for deffracting it into a zero-order diffracted beam and a first-order diffracted array of sampled, phase shifted beams, and a mask having a first and second apertures disposed at the Fourier transform plane of the first lens. A page composer having electrooptical transducers is positioned in the second aperture to receive the first-order diffracted array of beams to spatially optically modulate the incident beams in accordance with one of successive groups of binary signals. The zero-order diffracted beam is allowed to pass through the first aperture and the first-order diffracted array of spatially modulated beams are focused by the second lens to produce interference fringes between the wavefronts of zero- and first-order beams on a Fourier transform plane of the second lens on which a recording medium is positioned. The holographic beam splitter and the recording medium are…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.