Now, Japan's National Institute of Information and Communications Technology (NICT), in collaboration with Sony Semiconductor Solutions, has developed what they describe as "the world's first practical surface-emitting laser that employs quantum dots as the optical gain medium. The vertical-cavity surface-emitting laser (VCSEL / ˈvɪksəl /) is a type of semiconductor laser diode with laser beam emission perpendicular from the top surface, contrary to conventional edge-emitting semiconductor lasers (also called in-plane lasers) which emit from surfaces formed by cleaving. The Vertical-Cavity Surface-Emitting Laser (VCSEL), conceived by Kenichi Iga at Tokyo Institute of Technology in 1977, is notable for its single-mode operation, easy monolithic manufacturability, and frequency tunability. However, VCSELs typically operate in the near-infrared region, at wavelengths of 850 or 940 nm. Researchers have created a new technique for precise control of cavity length in GaN-based vertical-cavity surface-emitting lasers.
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