Abstract
Starting with next generation high density optical disc, commercial use of GaN based violet laser diodes (LD) has been adopted in many new fields, such as bio-medical, reprographic, exposure and etc. Recently, the lasing wavelength has broadened to cover from ultraviolet (UV) to blue-green region, which enabled other new applications. In this paper, current status of GaN based LDs in UV to Blue-green region are reported and next target is discussed.