Long-Lifetime True Green Laser Diodes with Output Power over 50 mW above 525 nm Grown on Semipolar \{20\bar{2}1\} GaN Substrates

True green GaInN laser diodes with a lasing wavelength above 525 nm under continuous wave operation have been successfully fabricated on semipolar {2021} GaN substrates by improving both the diode structure and epitaxial growth conditions. At a case temperature of 55 °C, their lifetime was estimated to be over 5000 h for an optical output power of 50 mW and over 2000 h at 70 mW.