POWER-MODULATED LASER DEVICES

摘要

An optical microscope 20 for examining surface features of a target surface, at a resolution, in one dimension, in the picometer-to-nanometer range. The microscope includes a laser 22 for use in producing a coherent output light beam 24, a lens 36 for focusing the output beam onto a target 38, and a photodetector 44 for measuring the power output of the beam. The focused beam is moved relative to the target surface in a defined time- and position-dependent pattern, with a portion of the light reflected from the target surface being reflected back into the laser. Changes in the measured power of the laser are then converted to position-dependent displacements, in the direction of the output beam. Also disclosed is an optical data storage apparatus and disc in which information is stored and read at multiple submicron depths.