Magneto-optic readout apparatus using polarization switching of readout beam
US5182735A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 6, 1989 |
| Grant date | Jan 26, 1993 |
| Priority date | — |
| Expiry date | Mar 6, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10545
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A magneto-optic playback apparatus which plays back information from a recording layer (RL) which exhibits different light absorption of left and right circular polarized beams emitted from a laser (L). The laser (L) operates in two different polarization modes, DE and TM. Polarization converter (PC) converts linear polarized radiation from the laser in one plane to one circular polarization orientation (left or right) in one direction of transmission, and then converts the opposite circular polarized radiation orientation back to linear polarization in the other direction of transmission. The laser switches between modes according to the magnetic orientation of the medium which is determined by the reflected light. Loss control element (LC) selectively increases the TE losses in the extended laser cavity. The self-coupling laser's operation in either the TE or TM mode depends on the differential absorption by the media of right (RCP) or left (LCP) handed circularly polarized beams.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.