Nowadays, with the rapid development of information technology, people have higher and higher requirements for optical storage capacity. At present, the most advanced optical storage technology is ().

Blu-ray or Blu-ray Disc (BD for short) uses blue laser with short wavelength (405 nm) to read and write data, hence its name. Up to now, Blu-ray is the most advanced large-capacity optical disc format. With the great progress of BD laser technology, users can store 25GB document files on a CD.