Recent progress in the commercialization of green- and blue-emitting laser diodes is creating opportunities to expand existing markets as well as enabling new growth segments. The advantages inherent in visible “direct diode” lasers are expected to drive market growth from displacement of other visible lasers in elastic applications segments within defense, industry, and medicine. Moreover, new applications in display and illumination will be created by converting users of nonlaser sources, such as specialty lamps and light-emitting diodes (LEDs), to laser diodes.
Visible laser applications were originally served by helium-neon and argon-ion gas lasers until the subsequent introduction of lamp-pumped solid-state lasers, diode-pumped solid-state lasers, infrared semiconductor lasers, and second harmonic generation (SHG) techniques. While these SHG laser systems are adequate for specialty blue and green laser applications today, they are still too inefficient, bulky, expensive, temperature sensitive, and fragile for broad deployment into high-volume applications. Whenever possible, red laser diodes are used because they are smaller and less expensive—but for many applications, red is not an optimal wavelength choice, and blue or green is required.