The name Blu-ray is derived from the blue-violet laser it uses to read and write to the chalcogenide disc. A Blu-ray Disc can 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 use 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 (currently 25GB, but test media is up to 100 gigabytes). Sony has released 50 gigabyte recordable BDs and will soon be releasing 50 gigabyte BD media discs. In August 2006, TDK developed a Blu-ray disk with a 200 gigabytes capacity