Optical arrangement for data reading and writing - use precisely-aligned read and write beams mounted on single tracking and focussing mechanism with alternative optic designs

摘要

Optical data storage and retrieval using the LIESST effect (Light Induced Excited Spin State Trapping) requires the use of separate light sources for reading and writing or erasing data. A light source (L1) and grating (G) produce a read beam (H1) and offset tracking beams (B1, B2), which are reflected from the disc surface (AT) to multiple detectors (A-F). The signals from these detectors form the data and control outputs. A separate light source (L2) for data write/erase operations may be mounted on the same tracking and focussing assembly. Alternative designs include multiple read/write light sources, and alternative tracking methods dispense with tracking beams (B1, B2).