It’s a phase change alloy, when writing a high powered laser is used to melt the alloy, when it cools quickly it becomes opaque. When erasing, a lower powered laser heats up the disc and returns it to its transparent state. A reading laser isn’t powerful enough to change the phases at all. So, you have the idea right… just no magnets involved.
CD-RWs are not magneto-optical. MiniDiscs are though.
I knew about MD’s, but I thought there was a metal alloy inside the CD-rw’s heated up by laser, alligned/written with magnets?
It’s a phase change alloy, when writing a high powered laser is used to melt the alloy, when it cools quickly it becomes opaque. When erasing, a lower powered laser heats up the disc and returns it to its transparent state. A reading laser isn’t powerful enough to change the phases at all. So, you have the idea right… just no magnets involved.