Optical disk tester using 680 nm laser head

Laser beam diameter size as small as 1.05 /spl mu/m/spl times/1.00 /spl mu/m was attained at the disk recording surface. This makes it possible to trace a narrow track less than 1.1 /spl mu/m from a next generation optical disk. The 5-step optical power control is also valid for high density data recording.<>