Continuous-wave operation of InGaN green laser diodes (LDs) on semipolar f2021g GaN substrates with output powers of over 100 mW in the spectral region beyond 530 nm is demonstrated. Wall plug efficiencies (WPEs) as high as 7.0-8.9% are realized in the wavelength range of 525-532 nm, which exceed those reported for c-plane LDs. The longest lasing wavelength has reached 536.6 nm under cw operation. These results suggest that the InGaN green LDs on the f20 21g plane are better suited as light sources for applications requiring wavelengths over 525 nm.

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.

We have realized a new method for the fabrication of a small mesa structure made of a few Bi2Sr2CaCu2O8+δ intrinsic Josephson junctions by using polyimide as an adhesive to glue a crystal on a substrate. It is demonstrated that this method provides a small mesa structure having only five junctions and exhibiting uniform tunneling characteristics. We describe the details of the fabrication process and the current–voltage characteristics for a typical mesa obtained, together with the short pulse tunneling spectroscopy results.