Red and blue laser diodes have been commercially available among the primary red-green-blue (RGB) colors, but there has been greater need for high output green laser diodes towards the development of high performance laser projectors and display devices. Currently, green lasers are generated by converting the wavelength of infrared laser light from a light source using optical materials, but the light source is large and expensive. In addition, conventional GaN-based green lasers have difficulties achieving sufficient luminosity as their performance is limited to an output power of several tens of milliwatt at a wavelength of 520 nm or less.
By introducing new techniques and improving the entire semiconductor laser production process, including structural design, crystal growth, wafer processing, and electrode configuration, the companies were able to successfully develop true green semiconductor laser with an optical output power of more than 100 mW at a wavelength of 530 nm.
The laser diode is also highly reliable as it realizes wall-plug efficiency of over 8%.
The development of true green semiconductor laser diode completes the three basic colors of the RGB laser light sources. Sumitomo Electric and Sony anticipate a wide variety of applications for this technology such as incorporation into advanced laser projectors with high luminosity and broad color gamut, as well as compact, light, energy-efficient laser projectors.