Multi Wavelengths Read-Out for Multi-Valued Mo Recording

We propose a new multi wavelengths read-out method which solves the fatal problem of decreasing the signal to noise ratio (SNR) in multi-valued magneto-optical (MO) recording. Theory and method to find the optimal condition are discussed and the two examples for the disks of RE-TM films and the combination of RE-TM and magnetic garnet films are investigated. This method provides theoretically 12.5 dB higher SNR than conventional one, and is suitable to realize 3-dimensional MO recording with the combination of the multi-valued MO recording proposed by Ohta and Shimazaki et al.[1]