Optical readout for optical storage with phase jump

A novel, to our knowledge, optical readout for optical storage with phase j ump is presented. In the readout scheme two coherent laser beams are focuse d on an optical disk with one beam scanning along pits and the other along land. When the probe beam scans across a pit, two phase jumps will take pla ce in the interference resultant of the two beams if the phase difference b etween two beams is prefixed at tau, resulting in a phase pulse of 180 deg. The slopes of rising and falling edges of the phase pulse are infinite, an d they are not affected by the intensity variation of the light source, str ay light and the vibration of the disk. Therefore this phase pulse can be u sed to read out the information on an optical disk. The use of phase jump w ill improve the signal-to-noise ratio of the readout, signal and enhance th e density of optical storage. An optical readout with phase jump, was const ruct;ed, Both the theoretical design and the experimental verification are conducted. Experimental results show that the proposed optical readout is f easible. (C) 1999 Optical Society of America.