What is Blu-ray™?

A Blu-ray Disc (BD) is a next-generation optical disc format meant for high-density storage of high-definition video and data.
The Blu-ray standard was jointly developed by a group of consumer electronics and PC companies called the Blu-ray Disc Association (BDA).
It is currently competing with the HD DVD format for wide adoption as the preferred next generation optical standard.

The name Blu-ray is derived from the blue-violet laser it uses to read and write to the disc.
A Blu-ray Disc will be able to store substantially more data than a DVD, because of the shorter wavelength (405 nm) of the blue-violet laser (DVDs use a 650-nm-wavelength red laser and CDs an infrared 780 nm laser), which allows more information to be stored digitally in the same amount of space. In comparison to HD DVD, which also uses a blue laser, Blu-ray has more information capacity per layer ... 25 gigabytes instead of 15.