Magneto-Optic (MO) rewritable recording is a reversible process that combines the use of magnetic and laser technologies to write, read, erase, and rewrite data. Rewritable recording is somewhat similar in concept to DASD recording. It uses a laser beam to heat the recording layer and then applies a magnetic field. The direction of magnetization changes only when the media is heated and the magnetic field is applied simultaneously. This process is used both at the time of recording and at the time of erasure. See Figure 1 for a pictorial overview of the MO optical media recording process.

Figure 1. Rewritable Magneto-Optic (MO) Recording Technique