Laser diodes in the yellow spectral region are important as compact and highly-efficient light sources for displays and measurements. Conventional III-V or III-nitride semiconductors are thought to have difficulty in realizing a laser diode of this spectral region. We demonstrated the continuous-wave operation of semiconductor laser diodes in the green-to-yellow spectral region with BeZnCdSe quantumwells. The lasing wavelength of the fabricated yellow laser diode was 570 nm. The light output power was as high as 50 mW with a low threshold current density.
