High SNR single wavelength readout for quadri-valued MO recording by detecting both magneto-optical rotation angle and ellipticity

摘要

A new high SNR readout method for quadri-valued MO recoding by detecting both MO rotation angle theta and ellipticity eta with only single wavelength is proposed. This advanced method is demonstrated by using a double -layered MO disk and green laser. Each layer of the double layered MO disk is independently read by an optical head for detecting theta and eta at 514.4 nm in wavelength.