Recording/Readout Mechanism of a Recordable Optical Disk
A recordable optical disk is a type of write once and read many (WORM) optical
disk. Information is recorded on a recordable optical disk using a photothermal
method. With laser irradiation on the recording layer, material molecules in the film
absorb energy from the laser pulses and undergo melting, evaporation, break, and
then form bumps, pits, or bubbles, which result in changes in the physical (optical)
properties at the irradiated spot (e.g., a reflectivity change). The two physically
(optically) different states before and after irradiation are used for information
storage [4].